Lower (Adjective, and Verb, to make), Lowest - Vine's Expository Dictionary of New Testament Words

Lower (Adjective, and Verb, to make), Lowest

[ A-1,Adjective,G2737, katoteros ]
the comparative degree of kato, beneath," is used in Ephesians 4:9, of Christ's descent into "the lower parts of the earth;" two of the various interpretations of this phrase are

(1) that the earth is in view in contrast to heaven,

(2) that the region is that of hades, the Sheol of the OT. Inasmuch as the passage is describing the effects not merely of the Incarnation but of the death and resurrection of Christ, the second interpretation is to be accepted; cp., e.g., Psalms 16:10; Psalms 63:9; where the Sept. has the superlative; Psalms 139:15; Acts 2:31. Moreover, as Westcott says, it is most unlikely that the phrase would be used to describe the earth. The word mere (plural of meros), "parts," would have no force in such a meaning.

[ A-2,Adjective,G2078, eschatos ]
"last, utmost, lowest," is rendered "lowest" in Luke 14:9-Luke 14:10, of the "lowest" place at a meal. See LAST.

[ B-1,Verb,G1642, elattoo ]
denotes "to make less" (elatton, "less"), and is used in the Active Voice in Hebrews 2:7, "Thou madest (Him) ... lower," and in the Passive in Hebrews 2:9, "was made ... lower," and John 3:30, "(I must) decrease," (lit., "be made less").

Vine's Expository Dictionary of New Testament Words