Probably from an obsolete diako (to run on errands; compare dioko); an attendant, i.e. (genitive case) a waiter (at table or in other menial duties); specially, a Christian teacher and pastor (technically, a deacon or deaconess) -- deacon, minister, servant.
see GREEK dioko
1. universally: of the servant of a king, Matthew 22:13; with the genitive of the person served, Matthew 20:26; Matthew 23:11; Mark 9:35; Mark 10:43 (in which passage it is used figuratively of those who advance others' interests even at the sacrifice of their own); τῆς ἐκκλησίας, of one who does what promotes the welfare and prosperity of the church, Colossians 1:25; διάκονοι τοῦ Θεοῦ, those through whom God carries on his administration on earth, as magistrates, Romans 13:4; teachers of the Christian religion, 1 Corinthians 3:5; 2 Corinthians 6:4; 1 Thessalonians 3:2 R T Tr WH text L marginal reading; the same are called διάκονοι (τοῦ) Χριστοῦ, 2 Corinthians 11:23; Colossians 1:7; 1 Timothy 4:6; ἐν κυρίῳ, in the cause of the Lord, Colossians 4:7; (Ephesians 6:21); ὁ διάκονος μου, my follower, John 12:26; τοῦ Σατανᾶ, whom Satan uses as a servant, 2 Corinthians 11:15; (ἁμαρτίας, Galatians 2:17); διάκονος περιτομῆς (abstract for concrete), of Christ, who labored for the salvation of the circumcised, i. e. the Jews, Romans 15:8; with the genitive of the thing to which service is rendered, i. e. to which one is devoted: καινῆς διαθήκης, 2 Corinthians 3:6; τοῦ εὐαγγελίου, Ephesians 3:7; Colossians 1:23; δικαιοσύνης, 2 Corinthians 11:15.
2. a deacon, one who, by virtue of the office assigned him by the church, cares for the poor and has charge of and distributes the money collected for their use (cf. BB. DD., Dict. of Christ. Antiq., Schaff-Herzog under the word 3. a waiter, one who serves food and drink: John 2:5, 9, as in Xenophon, mem. 1, 5, 2; Hier. 3, 11 (4, 2); Polybius 31, 4, 5; Lucian, de merced. cond. § 26; Athen. 7, p. 291 a.; 10, 420 e.; see διακονέω, 2 and διακονία, 5; (also Wetstein (1752) on Matthew 4:11).