Besiyata Dishmaya

Besiyata Dishmaya (Jewish Babylonian Aramaic: בְּסִיַּעְתָּא דִּשְׁמַיָּא, romanized: bəsiyyaʿtāʾ dišmayyāʾ) is a phrase meaning 'with the help of Heaven'.

The acronym בס״ד (BS"D) has become a popular term among Orthodox Jews, reproduced at the top of every written document (beginnings of correspondences, letters, notes, etc.)

This practice is not derived from any religious law of halakha, but it is considered an old accepted tradition.

The reason for the common use of the three-letter abbreviation, בס״ד, is probably because it does not contain the letter Hei (ה‎), that is used to imply the name of God, and for this reason, a page which contains these letters, without any other Torah content, does not require genizah (a process for writings that contain the name of God), and thus can be thrown away without fear of violation.

The book Toldot Yitzhak (The Offspring of Isaac), by Yitzhak Karo, offers the meaning of this custom of writing ב״ה‎ (B"H), at the top of every letter, with accordance to the biblical verse: "In all thy ways acknowledge Him, and He will direct thy paths" (Book of Proverbs 3:6).