There are various Hebrew and Greek words so rendered.

(1.) Heb. Jehovah, has been rendered in the English Bible
LORD, printed in small capitals. This is the proper name of the
God of the Hebrews. The form "Jehovah" is retained only in Ex.
6:3; Ps. 83:18; Isa. 12:2; 26:4, both in the Authorized and the
Revised Version.

(2.) Heb. 'adon, means one possessed of absolute control. It
denotes a master, as of slaves (Gen. 24:14, 27), or a ruler of
his subjects (45:8), or a husband, as lord of his wife (18:12).

The old plural form of this Hebrew word is "'adonai". From a
superstitious reverence for the name "Jehovah," the Jews, in
reading their Scriptures, whenever that name occurred, always
pronounced it "'Adonai".

(3.) Greek kurios, a supreme master, etc. In the LXX. this is
invariably used for "Jehovah" and "'Adonai."

(4.) Heb. ba'al, a master, as having domination. This word is
applied to human relations, as that of husband, to persons
skilled in some art or profession, and to heathen deities. "The
men of Shechem," literally "the baals of Shechem" (Judg. 9:2,
3). These were the Israelite inhabitants who had reduced the
Canaanites to a condition of vassalage (Josh. 16:10; 17:13).

(5.) Heb. seren, applied exclusively to the "lords of the
Philistines" (Judg. 3:3). The LXX. render it by satrapies. At
this period the Philistines were not, as at a later period (1
Sam. 21:10), under a kingly government. (See Josh. 13:3; 1 Sam.
6:18.) There were five such lordships, viz., Gath, Ashdod, Gaza,
Ashkelon, and Ekron.