From prasso; practice, i.e. (concretely) an act; by extension, a function -- deed, office, work.
see GREEK prasso
a. a doing, a mode of acting; a deed, act, transaction: universally, πράξεις τῶν ἀποστόλων (Griesbach; Rec. inserts ἁγίων, L Tr WH omit τῶν, Tdf. has simply πράξεις), the doings of (i. e. things done by) the apostles, in the inscription of the Acts; singular in an ethical sense: both good and bad, Matthew 16:27; in a bad sense, equivalent to wicked deed, crime, Luke 23:51; plural wicked doings (cf. our practices i. e. trickery; often so by Polybius): Acts 19:18; Romans 8:13; Colossians 3:9; (with κακῇ added, as Ev. Nicod. 1Ἰησοῦς ἐθεράπευσε δαιμονιζομένους ἀπό πράξεων κακῶν).
b. a thing to be done, business (A. V. office) (Xenophon, mem. 2, 1, 6): Romans 12:4.