There is a common practice for giving a nickname to a common coin. Here is a start for a list, please share other nicknames you know of, preferably mentioning the origin of the nickname. When additions come, I'll add them to this list.
Argentina, source: https://ventureoutspanish.com/money-talk-in-argentina/
1 peso: mango
10 pesos: diego
100 pesos: gamba
1000 pesos: luca
1,000,000 pesos: palo
Austria:
Due to international trade the Maria Theresia Thaler N#7393 obtained many nicknames:
1) in general in the Gulf as "the fat lady dollar" as it is still known today.
2) In Egypt: "Rial Nimsawi" - the German thaler, may relate to Austrians speaking German
3) Around the Red Sea: "Rial Kabir" - the big thaler
4) in Yemen: "Qirsh HaDsar" - the strong Piaster
5) in Yemen: "Qirsh Fransi" - the French Piaster, may relate to trade with the French
6) in Constaninople: "Qara Qirsh" - the black piaster
7) in Sudan: "Rial-abu- Nukta" - the father of points
8) in Somalia: "Shariq qirsh as-Suez al-fransiyy" - Eastern Piaster of French Suez
9) in Zanzibar. "Januairio" - January (??? - no clue why?)
10) in Suaheli: "Reali Meosi" - black thaler
11) in Abessinia: "Rial Abu Tair" - father of birds
12) in Khartoum: "Qirsh Rial Kusheriyy" - Piaster of birds
13) in Hungary: "A Nagyanya" - the great grandma
source: "Gábor Fazekas: Mária Terézia Tallér 1780"
Australia:
Shilling: deener
Belgium:
5 francs: knak, Flemish for 5 or 5 frank coin, mentioned in the online explanation for the origin of knaak (2½ gulden Netherlands)
20 francs: gouden Leopold (gold Leopold), refering to kings Leopold I and Leopold II
Canada, English nicknames:
5 cents silver: fish scale, due to their tiny size, alike US 3 cents
25 cents note: shinplaster, a term used in the U.S. and Australia for banknotes with little value
1 dollar: loonie, there is a loon (type of water bird) on the coin
2 dollars: toonie, a mix of two and loonie
Canada, Quebec nicknames:
25 cents: 30 sous, related to the pre 1760 days of a pound/livre/dollar being divided in 120 sous
50 cents silver: écu
Czechoslovakia/Czech Republic
1 koruna: kačka (duck), due to the first consonants being kč, just like Kč is short for Koruna československá (Czechoslovakian crown), as well as a newly minted koruna having the same colour as a (quite round) baby duckling
5 korun: búra/bůra/búro (storm), it also means 5 year prison term and in slang 5 goals scored, or a 5 for a failed exam (grades from 1 to 10, 6 passes), but for money ‘bor’ stems from the German ‘bar’ in ‘Bargeld’ (cash)
10 korun: pět (five), stemming from 10 korun = 5 gulden after the 1892 currency change from gulden to koruna
100 korun: kilo (kilo), due to crooks and swindlers using code language in order not to be understood, this became common use later, but it is not clear why ‘kilo’ was chosen as a code word
1000 korun: litr (liter), with 1 liter = 1000 milliliter similar to ‘litr korun’ = 1000 korun, initially again due to crooks using code language
1000 korun: tac (platter), due to the large size of the banknotes
El Salvador
1 colón: suegra (mother in law), N#4055 Christopher Columbus looking like a woman
France:
1 sol: sou, later 1 franc = 20 sou, hence 5 centimes was named sou
5 centimes with hole: sou, reusing the old nickname
25 centimes with hole: 5 sous
Germany:
Prussia: 1/6 thaler: Hundesechsteltaler, coin with details resembling two dogs (see: N#6822)
5 Pfennig: Sechser (sechs meaning six), remnant of the old duodecimal system
10 Pfennig, in duedecimal system 12 pfennig, even used for 10 Euro cents today: Groschen, stems from 1 Taler (Thaler) = 24 Groschen
Great Britain: see United Kingdom
India:
25 paisa: 4 annas, refering to the old rupee equaling 16 annas
50 paisa: 8 annas, see 25 paisa
Netherlands:
1 schelling (6 stuivers): scheepjesschelling, refering to the ship on the coin, scheepje meaning little ship
½ cent: halfje, refering to halve (half), extention ‘-je’ is Dutch for 'little'
5 cents: stuiver, refering to the historical stuiver coin with a value of 8 duit
10 cents: dubbeltje (in short duppie), refering to ‘dubbele stuiver’ (double stuiver)
25 cents: kwartje, a quarter of a gulden
1 gulden: florijn, the first guilder (according to what I found on internet) was named florijn, after the lily of Florence in the shield, but I'm not sure which one this refers to. The first gulden was made of gold, hence the name gulden, in 1521.
1 gulden: piek, starting late 17th century, guilder coins depicted a virgin holding a lance (lans, speer or piek in Dutch)
2½ gulden: rijksdaalder (in short riks), refering to the historical daalder, after decimalization 1 daalder obtained the value 1½ gulden
2½ gulden: knaak, the origin of this word is not known for sure, it may relate to German local language words Knoek or Kneek, or to the Flemish word knak (see Belgium)
5 gulden: gouden vijfje, golden 5 gulden coin, vijfje refering to vijf (five), extention ‘-je’ is Dutch for 'little'
10 gulden: gouden tientje, golden 10 gulden coin, tientje refering to tien (ten), extention ‘-je’ is Dutch for ‘little’
Some lesser used nicknames as well as names for banknotes are mentioned here: http://nl.wikipedia.org/wiki/Nederlandse_gulden and https://nl.wikipedia.org/wiki/Munt_(betaalmiddel)
Netherlands Antilles
½ cent: cen chikito, meaning little cent
1 cent: cen grandi, meaninf large cent
2½ cents: un (1) plaka
5 cents: sepelin/dos (2) plaka
10 cents: debchi/ kuater (4) plaka
25 cents: diez (10) plaka
50 cents: yotin
100 cents/gulden: heldu/florin, heldu stems from gulden; florin stems from florijn, see Netherlands 1 gulden
2½ gulden or florin: fuerte/dollar
Portugal
100 réis: tostão, already used for the 16th century silver coin
10 centavos: tostão, stemming from the 100 réis nickname, also used for larger amounts, like 25 tostões instead of 2,5 escudos
1000 escudos note: conto, originally used for larger sums of money, due to inflation it gained common use
Russia, some of these date centuries back, some have survived to this day:
1/4 kopeks: polushka
½ kopeks: denga, originating from Tatar meaning ‘small silver coin’ (source: https://en.m.wikipedia.org/wiki/Denga)
2 kopeks: grosh (up to 19th century; after Poland became part of the Russian Empire, 1 zloty = 15 kopeks and grosh (1/30 zloty) became 1/2 kopek), other names: semishnik, semitka, dvushka
3 kopeks: altyn, trioshnik
5 kopeks: pyatak/pyatachok
10 kopeks: grivennik
20 kopeks: dvukhgrivennyi/dvukhgrivennik
25 kopeks: chetvertak/polupoltinnik
50 kopeks: poltinnik
1 rubles: tselkovyi
10 rubles: chervonets
Spain
1 peseta: rubia, translates as blonde, probably refering to the colour of a newly minted copper coin
5 pesetas: duro, after the down size that became durito (small duro)
25 pesetas: 5 duros
100 pesetas: doblón, relates to the newly minted brass coin colour, resembling the old doblón gold coin
Syria:
2½ qirsh: نص فرنك (nasu firank) (half a franc): relating to the French Franc
5 qirsh: فرنك (firink) (franc): relating to the French Franc
10 qirsh: فرنكين (frinkin) (2 francs): relating to the French Franc
25 qirsh: ربع ليرة (rubue lira) (quarter lira): the Lira being the Syrian Pound
50 qirsh: نصف ليرة (nisf lira) (half lira): the Lira being the Syrian Pound
Sweden:
1 krona note 1874 to 1941: kotia (litterally: cow ten), relating to cheating in trade of cows, hiding 1 or 2 1 krona note(s) under a 10 kronor not on top with the same colour
1 krona: bagare/bagis (baker), though not as common as it used to be
1 krona: spänn (buckle), pix, riksdaler (currency prior 1873), used in plural like ‘25 spänn for a coke’ or ‘I paid 400 riksdaler for this shirt’
10 kronor coin: guldpeng (golden coin), because of it's colour
20 kronor note: Selma (after Selma Lagerlöf who is portrayed on the front)
1000 kronor note 1952-1973: Lakan (sheet), lök (onion) or papp (paperboard), due to the A4 paper size
1000 kronor note 1976-1988: lax (salmon), due to the pink colour
United Kingdom:
3 Pence: Thrup'ny bit
4 Pence, silver: Joey, sometimes used for the three pence e.g. threepenny joey
6 Pence: Tanner, named after the designer John S. Tanner. Dickens uses the term in Martin Chuzzlewit (xxxvii).
1 Shilling: Bob, Dickens used the term in Pickwick Papers.
2 Shillings [Florin]: Two-bob bit
5 Shillings [Crown]: Five bob
1 Pound: Quid, probably comes from the Latin 'quid pro quo' - 'something exchanged for something else'
low grade Henry VIII silver coinage: copper noses, even after little circulation the nose of the king on these coins obtained a copper colour
A long list of money related slang: https://www.learnenglish.de/slang/moneyslang.html
United States of America:
1 cent: penny (originating from the British penny)
3 cents, low grade silver: trimes or fish scales (due to their small size, alike Canadian 5 cents silver)
5 cents: nickel (refering to the material of 5 cents coins in the time of silver coinage)
10 cents: dime (originating from the French term disme (in modern French: dîme), meaning one tenth
25 cents: two bits, the US$ originally was based on the Spanish dollar, which was divided into 8 real or bits, hence ¼ dollar equals two bits
25 cents: quarter (a quarter of a dollar)
1 dollar: buck
1 dollar: Carter quarter or J.C. penny, the Susan B. Anthony dollars were authorized by a law signed by President Jimmy Carter on October 2, 1978, they became impopular due to their size being just a bit larger than the regular quarter
100 dollar note: Benjamin, with Benjamin Franklin on the banknote
Venezuela:
5 cents: Puya
12.5 céntimos: Locha
25 céntimos: Medio
50 céntimos: Real
5 Bolivares: Fuerte
100 Bolivares note: marron, refering to the brown colour
500 Bolivares note: orquidea (orchid), relating to the orchids on that banknote
Yugoslavia
1 dinar: kinta, stemming from qindar (1/100 Albanian lek), what Roma and Albanian beggers asked for in the period between WWI and WWII
10 dinar note 1920: banka, due to the big letters БАНКА/BANKA N#298984
100 dinar: glava (head), due to the head in the watermark of Miloš Obrenović prince of Serbia, or later Alexander I, King of the Serbs, Croats and Slovenes N#278549 N#206245
100 dinar: konj (horse in Slovenian), due to the Equestrian statue "Peace" by Antun Augustinčić, United Nations garden, New York, on N#206237
1000 dinar: сом/som (catfish), which may stem from the Uzbek word so'm (sum), later used to name the Uzbekistan currency



















