Defn: The twisting of an artery with a needle to arrest hemorrhage.

ACYCLIC
A*cyc"lic, a. [Pref. a- not + cyclic.]

Defn: Not cyclic; not disposed in cycles or whorls; as: (a) (Bot.)

Defn: Of a flower, having its parts inserted spirally on the receptacle. (b) (Org. Chem.) Having an open-chain structure; aliphatic.

ACYL
Ac"yl, n. [Acid + -yl.] (Org. Chem.)

Defn: An acid radical, as acetyl, malonyl, or benzoyl.

AD-
Ad-. Etym: [A Latin preposition, signifying to. See At.]

Defn: As a prefix ad- assumes the forms ac-, af-, ag-, al-, an-, ap-, ar-, as-, at-, assimilating the d with the first letter of the word to which ad- is prefixed. It remains unchanged before vowels, and before d, h, j, m, v. Examples: adduce, adhere, adjacent, admit, advent, accord, affect, aggregate, allude, annex, appear, etc. It becomes ac- before qu, as in acquiesce.

ADACT
Ad*act", v. t. Etym: [L. adactus, p. p. of adigere.]

Defn: To compel; to drive. [Obs.] Fotherby.