In Germany, June 27 is Siebenschläfertag (Seven Sleepers Day). The weather on that day is supposed to determine the average weather of the next seven weeks.

Haliphron atlanticus, a species of octopus, notable for its large size.

plural of seven-day wonder

Synonym of nine-day wonder / (uncommon) An individual or a process which requires only seven days to be perfected.

Seven English-language curse words, often referred to as being the most obscene. The words, in the order George Carlin originally listed them, are: shit, piss, fuck, cunt, cocksucker, motherfucker, and tits.

Synonym of at sixes and sevens

(gambling) A superstitious incantation hoping for a favorable initial (comeout) roll of seven or eleven in the game of craps.

(idiomatic) A striptease performance. / (idiomatic, by extension) The incremental disclosure of tantalizing bits of information.

Alternative form of dance of the seven veils

plural of seven-level screwdriver