katama : [adj.] which; what; which of the many.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

Katama (adj.) [cp. Vedic katama, interr. pron. with formation of num. ord., in function=katara, cp. antama > antara, Lat. dextimus>dexter] which, which one (of two or more) Vin ii.89; M i.7; J i.172; Miln 309; PvA 27. In some cases merely emphatic for ko, e. g. Vin i.30 (katamena maggena āgato?); D i.197 (katamo so atta -- paṭilābho?); J i.97; Sn 995; Miln 51. -- instr. katamena (scil. maggena) adv. by which way, how? Miln 57, 58.

Pali-English Dictionary, TW Rhys Davids, William Stede,

katama: a. 何者?

巴漢辭典 編者：(斗六) 廖文燦

katamá as, ā, at mfn. (superlative of 2. ka
• declined as a pronom., Gram. 236), who or which of many? (e.g. katamena pathā yātās te, by which road have they gone?)
• it is often a mere strengthened substitute for ka, the superlative affix imparting emphasis
• hence it may occasionally be used for 'who or which of two?' (e.g. tayoḥ katamasmai, to which of these two?)
• it may optionally be compounded with the word to which it refers (e.g. katamaḥ kaṭhaḥ, or katama-kaṭhaḥ, which Kaṭha out of many?)
• when followed by ca and preceded yatama an indefinite expression is formed equivalent to 'any whosoever', 'any whatsoever', &c. (e.g. yatamad eva katamac ca vidyāt he may know anything whatsoever). In negative sentences katama with cana or katama with api = not even one, none at all (e.g. na katamaccanâhaḥ, not even on a single day, on no day at all) [Page 246, Column 3]
• in addition to the above uses katama is said to mean 'best', 'excessively good-looking' (cf. 3. ka) RV. &c

Sanskrit-English Dictionary, by M. Monier William