Dismiss, v. t. [imp. & p. p. Dismissed; p. pr. & vb. n. Dismissing.]
Etymology: [L. dis- + missus, p. p. of mittere to send: cf. dimittere, OF. desmetre, F. démettre. See Demise, and cf. Dimit.]
1. To send away; to give leave of departure; to cause or permit to go; to put away. He dismissed the assembly. Acts xix. 41. Dismiss their cares when they dismiss their flock. Cowper. Though he soon dismissed himself from state affairs. Dryden.
2. To discard; to remove or discharge from office, service, or employment; as, the king dismisses his ministers; the matter dismisses his servant.
3. To lay aside or reject as unworthy of attentions or regard, as a petition or motion in court.
1 other Webster entry under this spelling
Dismiss, n.
Dismission. [Obs.] Sir T. Herbert.
Shades of meaning
Fernald has no entry of its own for dismiss; he lists it under banish, send.
Where he writes about it:
To despatch is to send hastily or very promptly, ordinarily with a destination in view; to dismiss is to send away from oneself without reference to a destination; as, to dismiss a clerk, an application, or an annoying subject. — from send
To discharge is to send away so as to relieve a person or thing of a load; we discharge a gun or discharge the contents; as applied to persons, discharge is a harsher term than dismiss. — from send