Composure, n.
Etymology: [From Compose.]
1. The act of composing, or that which is composed; a composition. [Obs.] Signor Pietro, who had an admirable way both of composure [in music] and teaching. Evelyn.
2. Orderly adjustment; disposition. [Obs.] Various composures and combinations of these corpuscles. Woodward.
3. Frame; make; temperament. [Obs.] His composure must be rare indeed Whom these things can not blemish. Shak.
4. A settled state; calmness; sedateness; tranquillity; repose. "We seek peace and composure." Milton. When the passions . . . are all silent, the mind enjoys its most perfect composure. I. Watts.
1 more senses
5. A combination; a union; a bond. [Obs.] Shak.
Shades of meaning
Fernald has no entry of its own for composure; he lists it under apathy, patience.
Where he writes about it:
Composure is freedom from agitation or disturbance, resulting ordinarily from force of will, or from perfect confidence in one's own resources. — from apathy