atthitā : [f.] existence; the fact of being present. || aṭṭhita (adj.), not steadfast.

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

Atthitā (f.) [f. abstr. fr. atthi cp. atthibhāva] state of being, existence, being, reality M i.486; S ii.17 (˚añ c˚ eva natthitañ ca to be and not to be); iii.135; J v.110 (kassaci atthitaŋ vā natthitaŋ vā jānāhi see if there is anybody or not); DhsA 394. -- Often in abl. atthitāya by reason of, on account of, this being so DhA iii.344 (idamatthitāya under this condition) PvA 94, 97, 143.

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