Rim, n.
Etymology: [As. rima, reoma, edge; cf. W. rhim, rhimp, a rim, edge, boundary, termination, Armor, rim. Cf. Rind.]
1. The border, edge, or margin of a thing, usually of something circular or curving; as, the rim of a kettle or basin.
2. The lower part of the abdomen. [Obs.] Shak. Arch rim (Phonetics), the line between the gums and the palate. -- Rim-fire cartridge. (Mil.) See under Cartridge. -- Rim lock. See under Lock.
1 other Webster entry under this spelling
Rim, v. t. [imp. & p. p. Rimmed; p. pr. & vb. n. Rimming.]
To furnish with a rim; to border.
Shades of meaning
Fernald has no entry of its own for rim; he lists it under bank.
He lists it without comment; the entries above explain its neighbors.