周

frequency meter; wavemeter

marginalization

Computing

frequency demultiplier; frequency divider

perirhinal; perinasal

Mathematics

angle at the circumference; circumferential angle; inscribed angle

periglacial

grave-site with circular embankment (Jomon period)

Botany

periderm

diurnal

Idiomatic expression

how others look at you; what others think about you

surrounding countries; neighboring countries; neighbouring countries

when you really think about it; on reflection; in actual fact; when all is said and done; all things considered; in the end

once again (fashionable, popular, etc.); back (in style)

round-the-world trip; circumnavigation; globe-trotting

being one or more laps behind (in a race)

being behind the times

consternation; falling into a panic; fluster; confusion; dismay; discomfiture

surrounding environment; ambient surrounding; one's surroundings

peripheral; peripheral device; accessory

making (something) known to everyone; publicizing as widely as possible; dissemination

round-the-world trip; world cruise

frequency band; waveband

Astronomy

period of revolution; orbital period

Astronomy

rotation period

circuit track; circular course

personal belongings; personal effects