This surname is derived from the name of an ancestor. 'the son of Cassandra' from the nick. Cass, a common girl's name in the 12th and 13th centuries. I only furnish a few instances:

Albric' fil, Cassandre, Cambridgeshire, 1273. Hundred Rolls.

Ralph fil. Cassandre, Cambridgeshire, ibid.

Cassandre (without surname), Huntingdonshire, ibid.

Cassandra Metcalfe, York, 1509:: Corpus Christi Guild (Surtees Society).

Casse Rumpe, Kent, 1273. Hundred Rolls.

Stephen Casse, Somerset, 1 Edward III: Kirby's Quest.

Johannes Case, 1379: Poll Tax of Yorkshire.

Willelmus Casson, 1379: ibid.

Cassander Danyll, 1379: ibid.

1676. John Casse and Elizabeth Bright: Marriage Lic. (Faculty Office).

1747. Married — Daniel Cass and Elizabeth Pritchard: St. George's Chapel, Mayfair.

King David I granted to the church of Dunfermline a ploughgate of land in Craigmillar reserving the liferent of the wife of Roger Cass, c. 1130 (RD., p. 11). "Long afterwards there were people of the name of Cass feuars of Monktonhall and other places under the Abbey of Dunfermline" (Lawrie, p. 336). John Cass in Dalkeith was summoned before the Privy Council in 1566 (RPC., I, p. 444), and Robert Cas, eldest son of Richard Cas of Fordell and John Cas, notary, are in record in 1610 (Laing, 1581). John Cas, butcher in Dalkeith, was heir of James Cas, his father, in 1642 (Inquis., 2688), and Mr. Alexander Case was parson of Pollvart in 1658 (ibid., 4352). As the old family of this name were feuars under the Abbey of Dunfermline their name may have been derived from the lands of Cash in the parish of Strathmiglo.

(Anglo-French-Latin) the common French Casse-1 the Latin Cassius [prob. from Latin cass-us, vain] 2 confused with Case: v. Case.

(French, English) Dweller at, or near, an oak tree or forest, or at a hedged enclosure; one who made and sold copper pots; the son of Cass, a pet form of Cassandra (helper of men).

This name is found in the H.R. and may be the Anglo-Norman cas, chance, hazard-probably with reference to the character, or some incident in the life, of the first person who bore it. So Hazard has become a family name. A family in Devonshire thus designated account for it by a tradition that, about two hundred years since, a foundling was laid at the door of a certain gentleman, to whom popular scandal attributed its paternity; the gentleman denied the allegation, but from motives of humanity had the infant taken care of, and, from the circumstance of its having been enclosed in a packing-case, imposed upon the poor foundling this curious appellation. The French case, from Latin casa, a mean house, cottage, or hut, is, however, a more likely etymon.

Cas, an ancient Irish personal name, found so early as the fifth century. See Macnamara.

(French.) Case. A hut, a hovel; Gaelic, cass, caise, steep; quick, hasty, passionate.

(Gaelic.) Cas, a verb, to turn against, to thwart, oppose; a difficulty, a trying situation, a cause. Cas, a castle, the primary sense is to separate, drive off, or hate; the radical sense of hatred is driving off.

There was a family of Case in Swaffham 200 years ago, and the name is still in the town; the rector of Erpingham in 1628 bore this name. Philip Case was mayor of Lynn in 1764; and early last century, Mr. Case, attorney, of Mildenhale, Suffolk, held property in Holm - by - the - Sea (Bl.). This name occurred in Suffolk in the time of Edward I. (H. R.).