Pronunciation: ' a-kri- ˌ tärk
Function: noun
Etymology: Greek akritos uncertain (fr. a- + kritos, verbal of krinein to decide) + arch ē beginning ― more at CERTAIN , ARCH-
Date: 1963
: any of a group of fossil one-celled marine planktonic organisms of uncertain and possibly various taxonomic affinities held to represent the earliest known eukaryotes