Definition of sesqui-
1 : one and a half times <sesquicentennial>
2 : containing half again as many atoms <sesquiterpene>
3 : intermediate : combination <sesquicarbonate>
Origin of sesqui-
Latin, one and a half, half again, literally, and a half, from semis half of an as, one half (probably from semi- + as as) + -que (enclitic) and; akin to Greek te and, Sanskrit ca, Gothic -h, -uh
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