\Bos"po*rus\ (b[o^]s"p[-o]*r[u^]s), n. [L.]
A strait or narrow sea between two seas, or a lake and a
seas; as, the Bosporus (formerly the Thracian Bosporus) or
Strait of Constantinople, between the Black Sea and Sea of
Marmora; the Cimmerian Bosporus, between the Black Sea and
Sea of Azof. [Written also {Bosphorus}.]