流

Meteorology

jet stream

(metaphorically) floating with the tide

Colloquial

Ogasawara-ryu (school of etiquette)

punctilious etiquette

Ogasawara-ryu (school of archery, incl. horseback archery)

Ogasawara-ryu (school of military strategy)

epidemic

Leonids

middle class

personnel exchange; people-to-people exchange

spread of rumours (esp. to influence stock prices); spread of rumors

distribution revolution

top-ranked firm; top-tier corporation; leading company; prestigious company; stellar company

Medicine

mumps

abortion

ferrofluid; magnetic fluid; magnetorheological fluid

Hozoin-ryu (school of sojutsu)

Idiomatic expression

to rain heavily; to be raining cats and dogs

to cry tears of joy; to weep for joy

popular singer; singer of pop songs

floating lanterns or offerings for the spirits of the deceased

Baseball

hitting to the opposite field

women's writing; literature written by women

impeded blood flow

Proverb

anyone can make a mistake; even Homer sometimes nods

Considered by Bashō to be fundamental

the principle of fluidity and immutability in haiku; haiku is both fluid and transitory, and eternal and immutable; an interchange between the transient and the immutable is central to the soul of haiku

Medicine

reflux esophagitis