period [LME] When first used, period referred to the time during which something such as a disease, ran its course. It goes back to Greek periodos ‘orbit, recurrence, course’, from peri- ‘around’ and hodos ‘way’. The sense ‘portion of time’ dates from the early 16th century, with the use of the word to mean ‘full stop’, now part of US English, late 16th. Peri is also found in peripatetic [LME] now meaning ‘wandering, travelling’ but from Greek peripatetikos ‘walking up and down’ and originally applied to followers of the ideas of Aristotle (384–322 bc), who is said to have walked about while teaching; and periphery [LME]. Hodos, the second part of period, is also found in episode [L17th], literally ‘coming in beside’ from epi ‘addition’ and eisodos ‘entry’ (formed from eis ‘into’ and hodos); and exodus, ‘departure’ formed in the same way using ex- ‘out of’. See also method.