Fausset's Bible Dictionary 
1. Daughter of Ishmael, Esau's wife, Bashemath. (See Bashemath .) In Genesis 28:9, the narrative, she is called Mahalath; in Genesis 36:3-4; Genesis 36:10; Genesis 36:13; Genesis 36:17, the Edomite genealogy, she is called Bashemath. They are two names for the same person, both being described as "daughter of Ishmael, and sister of Nebaioth." But Bashemath, daughter of Eros, is the same as Adah daughter of Elon. So that there were two Bashemaths.
2. One of Rehoboam's 18 wives ( 2 Chronicles 11:18). Her husband's cousin, daughter of David's son Jerimoth.
3. Title of Psalm 53 and Psalm 88. A poetical enigmatical description of the subject, "upon sickness," namely, man's spiritual malady ( Isaiah 1:5-6). Psalm 53 is an instructive warning (maschil) to the wicked, as Psalm 14 is for the comfort of the righteous when cast down by the prevailing "corruption." The addition Leannoth, from 'Anah "to afflict" (compare Psalms 14:15), in Psalm 88 expresses "concerning the sickness of affliction," i.e. Israel's disorganization. Praise songs are the comfort of the afflicted. Psalm 88 is the most gloomy throughout of all the psalms, therefore the title ( Shir ) praise song must refer to Psalm 89, which forms the latter part of one whole, of which Psalm 88 is the first part. The Maschil or "instruction" is that the afflicted should pour out their grief to God ( James 5:13). David and the sons of Korah after him delight in such poetical enigmas in titles of psalms. Gesenius and Ludolf derive Mahalath less probably from the Ethiopic Machlet , a "harp". Delitzsch explains it as a direction for singing in slow pensive tone, ("moestoso").
Smith's Bible Dictionary 
Mahalath. (Stringed Instrument).
1. The daughter of Ishmael, and one of the wives of Esau. Genesis 28:9.
2. One of the eighteen wives of King Rehoboam, apparently his first. 2 Chronicles 11:18 only. She was her husband's cousin, being the daughter of King David's son, Jerimoth.
3. The title of Psalms 53, and Mahalath-Leannoth , the title of Psalms 88. The meaning of these words is uncertain. The conjecture is that Mahalath is a guitar, and that Leannoth has reference to the character of the psalm, and might be rendered "To Humble Or Afflict", in which sense the root occurs in Psalms 88:7.
Easton's Bible Dictionary 
Bibliography Information Easton, Matthew George. Entry for 'Mahalath'. Easton's Bible Dictionary. https://www.studylight.org/dictionaries/eng/ebd/m/mahalath.html. 1897.
Morrish Bible Dictionary 
1. Daughterof Ishmael and wife of Esau. Genesis 28:9 . See BASHEMATH.
2. Daughter of Jerimoth and wife of Rehoboam. 2 Chronicles 11:18 .
3. Name in the title of Psalm 53 . Its meaning is not known. Some suppose that a mournful tune is referred to, or that it was written for a time of sorrow. Gesenius takes it as a harp or stringed instrument.
Hawker's Poor Man's Concordance And Dictionary 
The title of Psalms 53:1-6 and Psalms 88:1-18. The design is wholly conjectural, what the meaning of the phrase is. If the word be derived, as some have said, from Machol, it hath respect to singing. Some derive it from Chalah, signifying infirmity.
Holman Bible Dictionary 
Psalm 53:1 Psalm 88:1 1 Genesis 28:9 2 2 Chronicles 11:18 3 Psalm 88:1
Hastings' Dictionary of the Bible 
MAHALATH. 1. See Basemath, No. 1. 2. Wife of Rehoboam, 2 Chronicles 11:18 . 2 Chronicles 11:3 . See Psalms, p. 772 a .
American Tract Society Bible Dictionary 
In the title of Psalm 53:1; 88:1 , is conjectured to refer to the tune or the instrument used in chanting these Psalms; or a Gengstenberg and Alexander suggest, the spiritual malady which they lament.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
(Heb. Machcalath', מִהֲלִת , a Lute, otherwise the title of a song) the name of two women. See below.
1. (Sept. Μαελέθ ,Vulg. Maheleth. ) The daughter of Ishmael, and third wife of Esau ( Genesis 28:9); elsewhere called BASHEMATH ( Genesis 36:3); but the Samar. Pent. has Mahalath in both passages. (See Esau).
2. (Septuag. Μολάθ v. r. Μοολάθ , Vulg. Malhalath. ) The daughter of Jerimoth. granddaughter of David. and wife of Kehoboam (2 Chronicles xi. 18). B.C. 973. "She was thus her husband's cousin, being the daughter of king David's son. who was probably the child of a concubine, and not one of his regular family. Josephus, without naming Mahalath, speaks of her as ‘ a kinswoman' ( Συγγενῆ Τινα , A nt. 8:10, 1). No children are attributed to the marriage. nor is she again named. The ancient Hebrew text (K-ethib) in this passage has ‘ son' instead of daughter.' The latter, however, is the correction of the Keri, and is adopted by the Sept., Vulg, and Targum, as well as by the A. V."
International Standard Bible Encyclopedia 
ma´ha - lath ( מחלת , maḥălath ):
(1) In Genesis 28:9 the name of a wife of Esau, daughter of Ishmael, and sister of Nebaioth, called in Genesis 36:3 , Basemath (which see). The Samaritan Pentateuch, however, throughout Genesis 36 retains "Mahalath." On the other hand, in Genesis 26:34 Basemath is said to be "the daughter of Elon the Hittite," probably a confusion with Adah, as given in Genesis 36:2 , or corruption may exist in the lists otherwise.
(2) One of the 18 wives of Rehoboam, a grand-daughter of David ( 2 Chronicles 11:18 ).
(3) The word is found in the titles of Psalm 53:1-6 (the Revised Version (British and American) "set to Mahalath") and Ps 88 (the Revised Version (British and American) "set to Mahalath Leannoth," margin "for singing"). Probably some song or tune is meant, though the word is taken by many to denote a musical instrument. Hengstenberg and others interpret it as indicating the subject of the Psalms. See Psalms .
Kitto's Popular Cyclopedia of Biblial Literature 
Ma´halath, the title of Psalms 53, 88 [[[Psalms, Book Of]]]
- Mahalath from Fausset's Bible Dictionary
- Mahalath from Smith's Bible Dictionary
- Mahalath from Easton's Bible Dictionary
- Mahalath from Morrish Bible Dictionary
- Mahalath from Hawker's Poor Man's Concordance And Dictionary
- Mahalath from Holman Bible Dictionary
- Mahalath from Hastings' Dictionary of the Bible
- Mahalath from American Tract Society Bible Dictionary
- Mahalath from Cyclopedia of Biblical, Theological and Ecclesiastical Literature
- Mahalath from International Standard Bible Encyclopedia
- Mahalath from Kitto's Popular Cyclopedia of Biblial Literature