The tunic worn like the shirt next the skin (Leviticus 16:4; Cant. 5:3; 2Sam 15:32; Exodus 28:4; 29:5). The "coats of skins" prepared by God for Adam and Eve were probably nothing more than aprons (Genesis 3:21). This tunic was sometimes woven entire without a seam (John 19:23); it was also sometimes of "many colours" (Genesis 37:3; RSV marg., "a long garment with sleeves"). The "fisher's coat" of John 21:7 was obviously an outer garment or cloak, as was also the "coat" made by Hannah for Samuel (1 Samuel 2:19). (See DRESS .)
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Coat'". "Easton's Bible Dictionary".