From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): ( a.) Being alone; belonging to, or being, that of which there is but one; unique.

(2): ( a.) Standing by itself; out of the ordinary course; unusual; uncommon; strange; as, a singular phenomenon.

(3): ( n.) The singular number, or the number denoting one person or thing; a word in the singular number.

(4): ( n.) An individual instance; a particular.

(5): ( a.) Departing from general usage or expectations; odd; whimsical; - often implying disapproval or consure.

(6): ( a.) Distinguished as existing in a very high degree; rarely equaled; eminent; extraordinary; exceptional; as, a man of singular gravity or attainments.

(7): ( a.) Separate or apart from others; single; distinct.

(8): ( a.) Denoting one person or thing; as, the singular number; - opposed to dual and plural.

(9): ( a.) Each; individual; as, to convey several parcels of land, all and singular.

(10): ( a.) Existing by itself; single; individual.

(11): ( a.) Engaged in by only one on a side; single.

King James Dictionary [2]

SIN'GULAR, a. L. singularis,from singulus, single.

1. Single not complex or compound. That idea which represents one determinate thing, is called a singular idea, whether simple, complex or compound. 2. In grammar, expressing one person or thing as the singular number. The singular number stands opposed to dual and plural. 3. Particular existing by itself unexampled as a singular phenomenon. Your case is hard, but not singular. 4. Remarkable eminent unusual rare as a man of singular gravity, or singular attainments.

SIN'GULAR, n. A particular instance. Unusual.

International Standard Bible Encyclopedia [3]

sin´gū́ - lar  : "Pertaining to the single person," "individual," and so sometimes "unusual," "remarkable." So The Wisdom of   Song of Solomon 14:18 , the King James Version "the singular diligence of the artificer" ( φιλοτιμία , philotimı́a , "love of honor," the Revised Version (British and American) "ambition"). In   Leviticus 27:2 by "when a man shall make a singular vow" the King James Version seems to have understood a "personal" or "private" vow. the Revised Version (British and American) has "accomplish a vow," with margin "make a special vow." Compare the same phrase ( yaphlı̄' ( yephallē' ) nedher ) used of the Nazirite vow in  Numbers 6:2 .

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [4]

a word used by old writers in the sense of incomparable, matchless, of unequalled excellence. The following examples are taken from king Edward VI's Primer: "Breathe into my heart by thy Holy Spirit this most precious and singular gift of faith, which worketh by charity, that When thou shalt call me out of this careful life [a life full of cares], I may enjoy that thy most singular and last benefit, which is everlasting glory through Jesus Christ our Lord." Staunton, Dict. of the Church, s.v.