A bird of the genus Hirundo, esp. H. rustica, a well-known migratory bird with long pointed wings and forked tail, having a swift curving flight…

concrete. A deep place or cavity, an abyss; a deep part of the sea, etc. Obsolete.

A deep place in the earth, etc.; a deep pit, cavity, valley; an abyss; a depression in a surface.

Any deep immeasurable space; a profound chasm or gulf. Also figurative. Cf. abyss, n. 2, 3.

A deep, dark place in the sea or land; a gulf, abyss, or chasm; a cave or cavern. Frequently in plural.

A deep place in the earth, etc.; a deep pit, cavity, or valley (obsolete); plural the deep or lowest part of a pit, cavity, etc. (rhetorical).

A yawning chasm or abyss; an opening in the earth produced by an earthquake or volcanic action; a vast ravine or gorge. a fiery gulf, gulf of fire…

A steep downward slope; an abyss, gulf.

A deep black gulf or abyss; a name locally applied to holes or pools popularly supposed to be bottomless. Cf. kettle, n. 4c.

An abysm or abyss.

An abyss, gulf, or chasm.

(under-, prefix1 affix 2b(c).)

U.S. U.S. regional (New England). A deep narrow gorge or ravine with steep sides. Also: a stream in such a gorge.

An abyss, a chasm, a gulf. Obsolete.

A gaping fissure or opening; an abyss.