Who
King James Dictionary [1]
Who, pron. relative. pron. hoo. L. Who is undoubtedly a contracted word in English as in Latin. See What and Wight.
1. Who is a pronoun relative, always referring to persons. It forms whose in the genitive or possessive case, answering to the L. Cujus, and whom in the objective or accusative case. Who, whose and whom, are in both numbers. Thus we say, the man or woman who was with us the men or women who were with us the men or women whom we saw. 2. Which of many. Are you satisfied who did the mischief? 3. It is much used in asking questions as, who am I? Who art thou? Who is this? Who are these? In this case, the purpose is to obtain the name or designation of the person or character. 4. It has sometimes a disjunctive sense.
There thou tellst of kings, and who aspire who fall, who rise, who triumph, who do moan.
5. Whose is of all genders. Whose book is this?
This question whose solution I require--
As who should say, elliptically for as one who should say.
Webster's Dictionary [2]
(1): ( object.) Originally, an interrogative pronoun, later, a relative pronoun also; - used always substantively, and either as singular or plural. See the Note under What, pron., 1. As interrogative pronouns, who and whom ask the question: What or which person or persons? Who and whom, as relative pronouns (in the sense of that), are properly used of persons (corresponding to which, as applied to things), but are sometimes, less properly and now rarely, used of animals, plants, etc. Who and whom, as compound relatives, are also used especially of persons, meaning the person that; the persons that; the one that; whosoever.
(2): ( pron.) One; any; one.
