Caul

kôl :

(1) יתרת , yōthereth ( Exodus 29:13 ), the large lobe or flap of the liver, which is usually mentioned together with the kidneys and the fat as the special portions set aside for the burnt offering ( Leviticus 3:4 , Leviticus 3:10 , Leviticus 3:15; Leviticus 4:9; Leviticus 7:4; Leviticus 8:16 , Leviticus 8:25; Leviticus 9:10 , Leviticus 9:19 ).

(2) סגור , ṣeghōr (from the root ṣāghar , "to enclose," "shut up"), Hosea 13:8 , literally the enclosure or covering of the heart, the caul or pericardium, or perhaps the chest as surrounding the heart. It must not be forgotten, however, that the expression may be taken in the sense of "mailcoat of the heart," i.e. hardened heart, which is shut to the influence of God's grace. So Luther and many modern translators and commentators.