Of Hebrew origin (shabbath); the Sabbath (i.e. Shabbath), or day of weekly repose from secular avocations (also the observance or institution itself); by extension, a se'nnight, i.e. The interval between two Sabbaths; likewise the plural in all the above applications -- sabbath (day), week.
see HEBREW shabbath
1. the seventh day of each week, which was a sacred festival on which the Israelites were required to abstain from all work (Exodus 20:10; Exodus 31:13; Deuteronomy 5:14);
a. singular σάββατον and τό σάββατον: Mark 6:2; ( b. plural, τά σαββάτων (for the singular) of a single sabbath, sabbath-day (the use of the plural being occasioned either by the plural names of festivals, as τά ἐγκαίνια, ἄζυμα, γενέσια, or by the Chaldaic form שַׁבָּתָא (Winers Grammar, 177 (167); Buttmann, 23 (21))): Matthew 28:1; Colossians 2:16 (Exodus 20:10; Leviticus 23:32 etc.; τήν ἑβδόμην σάββατα καλουμεν, Josephus, Antiquities 3, 6, 6; add, 1, 1, 1; (14, 10, 25; Philo de Abrah. § 5; de cherub. § 26; Plutarch, de superstitione 8); τήν τῶν σαββάτων ἑορτήν, Plutarch, symp. 4, 6, 2; hodie tricesima sabbata, Horace sat. 1, 9, 69; nowhere so used by John except in the phrase μία τῶν σαββάτων, on which see 2 below); ἡ ἡμέρα τῶν σαββάτων, Luke 4:16; Acts 13:14; Acts 16:13 (Exodus 20:8; Exodus 35:3; Deuteronomy 5:12; Jeremiah 17:21f); τοῖς σάββασιν and ἐν τοῖς σάββασιν (so constantly (except Lachmann in Matthew 12:1, 12) by metaplasm for σαββάτοις, cf. Winers Grammar, 63 (62); (Buttmann, 23 (21))) on the sabbath-day: Matthew 12:1(see above),5, 10-12 (see above); Mark 1:21; Mark 2:23; Mark 3:2, 4; Luke 4:31; Luke 6:9 (R G L marginal reading) (1 Macc. 2:38; the Sept. uses the form σαββάτοις, and Josephus both forms). On the precepts of the Jews with regard to the observance of the sabbath, which were for the most part extremely punctilious and minute, cf. Winers RWB, under the word Sabbath; Oehler in Herzog xiii. 192ff (revised by Orelli in edition 2 vol. xiii. 156ff); Schürer, Zeitgesch. 2te Aufl. § 28 II.; Mangold in Schenkel see, p. 123f; (BB. DD., 2. seven days, a week: πρώτη σαββάτου, Mark 16:9; δίς τοῦ σαββάτου, twice in the week, Luke 18:12. The plural is used in the same sense in the phrase ἡ μία τῶν σαββάτων, the first day of the week (see εἷς, 5) (Prof. Sophocles regards the genitive (dependent on ἡμέρα) in such examples as those that follow (cf. Mark 16:9 above) as equivalent to μετά with an accusative, the first day after the sabbath; see his Lex., p. 43 par. 6): Matthew 28:1; Mark 16:2; Luke 24:1; John 20:1, 19; Acts 20:7; κατά μίαν σαββάτων (L T Tr WH σαββάτου), on the first day of every week, 1 Corinthians 16:2.