Etymology: Origin uncertain. Compare Dutch kriel small person, dwarf, small bird (1599 in Kiliaan), perhaps the same word as kriel collective term for a group of small things, small fry, small potatoes, which is in turn probably < krielen (Middle Dutch crielen ) to swarm, to teem (with) (of uncertain origin). The resemblance in form and meaning between the Dutch and English words makes a connection likely, but the hypothesis of a borrowing < Dutch presents formal problems: the diphthongal pronunciation shown by the β. forms would suggest a relatively early date of borrowing (for the word to have participated in the first phase of the Great Vowel Shift); the α. forms could perhaps be explained as showing rounding of the first element of the diphthong shown by the β. forms (a phenomenon found in some Scots dialects); but the γ. forms would remain difficult to explain (they could perhaps result from association with crawl v.¹: compare forms at that entry).In Irish English (northern) a derivative formation crowlie , crawley , croilie , crouly is also found (compare -y suffix⁶).

Etymology: apparently onomatopoeic, having the initial part of croak and kindred words, while the latter part expresses prolonged sound: compare growl.