The oral or buccal cavity and its related structures.

The end of a horn that has the larger cross- sectional area.

1. The place where one body of water discharges into another. Also known as influx.

2. The entrance or exit of a geomorphic feature, such as of a cave or valley.

1. The end of a shaft, adit, drift, entry, or tunnel emerging at the surface.

2. The collar of a borehole.

Something resembling a mouth, that is, a place where one thing enters another or an opening at the receiving end of a container or enclosure.