Etymology: Ultimately related to Old English frosc frosh n.¹ and its cognates in other Germanic languages (see below), although the nature of the relationship is uncertain; the present word was probably originally an alteration of frosc as a result of association with docga dog n.¹ and other words denoting animals which are listed at that entry, in which the geminate consonant perhaps originally had a hypocoristic motivation; however, other explanations are perhaps possible. Connection with a number of other words in fr- denoting a frog in English and other Germanic languages is much less certain (see (3) and (4) below). The stem-final geminated consonant in Old English frogga , frocga is unusual and difficult to explain; it is probably related to the similar geminate shown by docga dog n.¹ and other words denoting animals which are listed at that entry. As noted above, it is possible that frogga shows an alteration of Old English frosc (also frox , forsc : see frosh n.¹) by association with this group of words, perhaps originally as a hypocoristic derivative, although it is perhaps also possible that frogga shows an isolated reflex of a Germanic base ultimately cognate with that of frosc (see further below). Words for a frog with initial fr- in Old English and other Germanic languages can be divided into four groups: (1) Old English frosc (also frox , forsc : see frosh n.¹), cognate with Middle Dutch vorsch , versch , vorsche (Dutch vors , now chiefly in kikvors ), Middle Low German vrosch , vorsch , vors , Old High German frosc (Middle High German vorsch , vors , German Frosch ), Old Icelandic froskr , Swedish (regional) frosk , further etymology uncertain, perhaps ultimately a derivative < an extended form of an Indo-European verbal base with the meaning ‘to hop’, reflected by Sanskrit pru- to leap (probably further related to plu- to swim (see flow v.; perhaps compare plavaga , plavaṅga monkey, frog); the same extended form is perhaps reflected also by Russian pryt′ speed, quickness, liveliness (late 18th cent., although earlier currency is perhaps implied by the adverb adjective prytkij ‘quick, lively’ (17th cent. in Old Russian) and the adverb prytko ‘quickly, nimbly, in a lively manner’ (1562 in Old Russian); now chiefly in fixed phrases, e.g. vo vsju pryt′ ‘as fast as one's legs can carry one’), and (with added velar suffix) prygat′ to leap, to jump, to hop (late 18th cent.); perhaps compare also Lithuanian sprugti ‘to escape’, which may be < the same Indo-European base with movable s- , although the evidence to support such a reconstruction is very limited. (2) frog n.¹, which, as suggested above, could show an alteration or variant within Old English of frosc , probably by association with the group of words denoting animals discussed at dog n.¹, or which could perhaps (less probably) show the only attested reflex of a different formation < the same Germanic verbal base as frosc and its cognates. (3) Middle English frūde froud n., which (although also beginning with fr- ) is probably unrelated; this is perhaps ultimately (with operation of Verner's Law) < an ablaut variant (showing also sound-symbolic lengthening of the vowel) of the same Germanic base as Old Icelandic frauðr , Old Swedish fördh , frödher (Swedish frö ), Old Danish frødh (Danish frø ); perhaps ultimately < the same base as froth n., hence referring to the slimy skin of a frog. (It is also possible that Middle English frode at froud n. Forms may show another distinct word in this same group.) (4) Old Icelandic frauke , which probably shows a derivative of the forms under (3). It is possible that froke at Forms could instead show a borrowing of this word. Many scholars have attempted to link all four groups of forms, assuming a variety of different starting points, but none of these attempts has been wholly successful.In sense A. 3 after classical Latin rānula ranula n. The phrase frog in the throat n., frog in one's throat n. at Phrases 3 is probably not connected with this, instead alluding purely to the croaky call of a frog. Compare German einen Frosch im Hals haben in the same sense. (German Frosch also occurs in sense A. 3, but again the phrase is probably independent of this.) In sense A. 5 probably after German Frosch, a transferred use of Frosch frog on account of its shape; compare am Frosch (played) near the nut. In senses A. 3, A. 7, and probably also A. 6 on account of the resemblance to a frog in shape or appearance. It is possible that sense A. 6 could instead show a transferred use of frog n.², again on account of its shape. Old French froit , froiz frog shows a borrowing < a Germanic language. With sense A. 8 (in use with reference to persons or individuals) compare early use as a byname and surname: Nicholas Frog’ (1207), William le Frogge (1275), William Frogge (1332), etc. The precise reasons for the specific uses in senses A. 9 and A. 10 are uncertain; in A. 9 perhaps with allusion to the marshy and low-lying nature of the Low Countries (compare later Froglander n., frogland n.); in A. 10 perhaps with allusion to the supposed popularity among French people of frogs' legs as a dish, and perhaps partly also on account of the shared initial consonant cluster in frog n.¹ and French adj.; however, both senses could simply show narrowing of sense A. 8 to identify the inhabitants of countries which were near neighbours and frequent rivals of Britain.

Etymology: Origin uncertain. Probably a specific use of frog n.¹, perhaps after ancient Greek βάτραχος frog, in Hellenistic Greek or Byzantine Greek also this part of a horse's hoof (see batracho- comb. form). Compare frush n.² (and perhaps compare the parallel between frog n.¹ and frosh n.¹).Association in sound with a regional variant of French fourchette (1680 in this sense; transferred use of fourchette fourchette n.) or with one of its Romance cognates is less likely.

Etymology: Origin unknown. N.E.D. (1898) suggests as etymon Portuguese froco ( < classical Latin floccus flock n.²), which it comments ‘has much the same sense’, but no use denoting a type of fastening is recorded in dictionaries of Portuguese.

Etymology: Origin uncertain. Perhaps a transferred use of frog n.¹, on account of a supposed resemblance of the (triangular) metal plate to a frog; or perhaps even a transferred use of frog n.², again on account of a supposed resemblance in shape.

Etymology: < frog n.¹ With sense 3 compare earlier frogging n.¹, frogger n.