From an unused root meaning to testify; a witness -- record.
H7717. sahed
[שָׂהֵד] noun [masculine] witness (Aramaic loan-word = Hebrew עֵד; √ סְהַד ); — suffix שָֽׂהֲדִי Job 16:19 ("" עֵדִי). — שָֽׂהֲדוּתָא Genesis 31:47 see Biblical Aramaic Lexicon.
שׂהר (√ of following; compare Arabic new moon ( is make conspicuous, notorious); Ethiopic id.; סִיהֲרָא ᵑ7, Syriac moon; Old Aramaic שהר moon-god Lzb373).
[שָֽׂהֲדוּ] noun feminine testimony (√ שְׂהַד = סְהַד ᵑ7 testify, Syriac , Arabic testify, compare Biblical Hebrew [שָׂהֵד] (once, as loan-word) KAramaic 86; Egyptian Aramaic plural שהדיאֹ witnesses Cooke404 S-CA. 15 + often); — emphatic שָֽׂהֲדוּתָא Genesis 31:47 ("" Biblical Hebrew עֵד).