|Easton's Bible Dictionary|
(1.) Hebrew kiddah', i.e., "split." One of the principal spices of the holy anointing oil (Exodus 30:24), and an article of commerce (Ezek. 27:19). It is the inner bark of a tree resembling the cinnamon (q.v.), the Cinnamomum cassia of botanists, and was probably imported from India.
(2.) Hebrew pl. ketzi'oth (Psalm 45:8). Mentioned in connection with myrrh and aloes as being used to scent garments. It was probably prepared from the peeled bark, as the Hebrew word suggests, of some kind of cinnamon.
Noah Webster's Dictionary
1. (n.) A genus of leguminous plants (herbs, shrubs, or trees) of many species, most of which have purgative qualities. The leaves of several species furnish the senna used in medicine.
2. (n.) The bark of several species of Cinnamomum grown in China, etc.; Chinese cinnamon. It is imported as cassia, but commonly sold as cinnamon, from which it differs more or less in strength and flavor, and the amount of outer bark attached.
Int. Standard Bible Encyclopedia
kash'-a: Two Hebrew words,
(1) qiddah, which is mentioned, along with myrrh, cinnamon, calamus and olive oil, as one of the ingredients of the "holy anointing oil" (Exodus 30:24); it was, too, one of the wares in which Vedan and Javan traded with Tyre (Ezekiel 27:19); it is identified in the Peshitta and the Targum with (2).
(2) qetsi`oth (plural only, probably referring to the strips of bark), a word from which is derived the Greek kasia, and hence, cassia (Psalm 45:8).
It is probable that both (1) and (2) refer to Cassia lignea, the inner bark of Cinnamomum cassia, a plant growing in eastern Asia closely allied to that which yields the cinnamon of commerce. It is a fragrant, aromatic bark and was probably used in a powdered form. Both as an ingredient in unguents and as one of the perfumes at funerals, cassia, like cinnamon, was much used by the Romans. The cassia of Scripture must be clearly distinguished from the entirely distinct Cassia lanceolata and C. obovata which yield the familiar senna. The proper name KEZIAH (which see) is the singular form of ketsi`oth.
E. W. G. Masterman
Cassia (3 Occurrences)
Exodus 30:24 and of cassia five hundred, after the shekel of the sanctuary; and a hin of olive oil. (WEB KJV JPS ASV BBE DBY WBS YLT NAS RSV NIV)
Psalms 45:8 All your garments smell like myrrh, aloes, and cassia. Out of ivory palaces stringed instruments have made you glad. (WEB KJV JPS ASV DBY WBS YLT NAS RSV NIV)
Ezekiel 27:19 Vedan and Javan traded with yarn for your wares: bright iron, cassia, and calamus, were among your merchandise. (WEB KJV JPS ASV DBY WBS YLT NAS RSV NIV)