'Period' is Greek for 'a way around' — 'peri-' (around) + 'hodos' (path). A complete circuit of time.
A length of time; a portion of time characterized by particular events or qualities; the punctuation mark (.) used at the end of a sentence.
From Old French periode, from Latin periodus, from Greek periodos (a going around, a circuit, a cycle, a recurring interval), compounded from peri- (around, about) + hodos (a way, a road, a path, a journey). Hodos comes from Proto-Indo-European *sed- or a root related to *h₁ed- (path, going). The compound literally means a way around — a complete circuit. Ancient Greek rhetoricians used periodos for a well-rounded sentence
The punctuation mark '.' is called a 'period' because it marks the end of a complete sentence — a complete 'circuit' of thought. Greek rhetoricians used 'periodos' for a complete, well-rounded sentence, and the dot at its end inherited the name. In British English, the same mark is called a 'full stop