'single-nucleate' is a compound of 'single' and 'nucleate'. 'single' originates from Old English (via Middle English) 'single' ultimately related to Latin 'singulus' meaning 'one'. 'nucleate' originates from Modern Latin 'nucleatus', from Latin 'nucleus' meaning 'kernel' or 'core'.

'nucleate' developed from Latin 'nucleus' to Medieval/Modern Latin 'nucleatus' and was adopted into English scientific usage as 'nucleate' in the 18th–19th centuries; 'single' has remained in English from Old/Middle English to modern 'single', and the compound 'single-nucleate' is formed by joining these elements for biological description.

Initially, 'nucleate' referred to having or relating to a nucleus (from 'nucleus' meaning 'kernel/core'), and in compounds like 'single-nucleate' the meaning has stayed consistent: indicating the presence of a single nucleus.