1. A word of interrogation in all genders; as, which man? Which woman? Which house? Also a relative in reference to things neuter.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• wisch,
• shoch,
• wihch,
• whivh,
• whiched,
• whieh,
• wiyh,
• whichx,
• weish,
• whjich,
• whichn,
• waish,
• whiah,
• whifh,
• whitch,
• shitch,
• wsitch,
• whixh,
• chirch,
• wichi

• whacky,
• whack,
• whacko,
• whoosh,
• whish.

The adjective form of "which" is "whichsoever". However, this form is rather uncommon and archaic.

There is no plural form for the word "which". It remains the same in both singular and plural contexts.

The singular form of the word "Which" is "Which". The word does not change in form when used as a singular or plural pronoun.