samāpanna : [pp. of samāpajjati] entered upon; engaged in.

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

Samāpanna [pp. of samāpajjati] having attained, got to, entered, reached S iv.293 (saññā -- nirodhaŋ); A ii.42 (arahatta -- maggaŋ entered the Path); Dh 264 (icchālobha˚ given to desire); Kvu 572 (in special sense= attaining the samāpattis).

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

sam-āpanna mfn. fallen into (acc.) MBh
• meeting with (?) Divyâv
• having ib
• one who has undertaken (instr.) Kāraṇḍ
• arrived, come, happened, occurred Hit. (v. l. sam-āsanna)
• furnished or endowed with (comp.) MBh. R. &c
• perfect, proficient (in any science) W
• accomplished, concluded, done L
• distressed, afflicted ib
• killed ib
• n. death L

Sanskrit-English Dictionary, by M. Monier William

 

mnyam par bzhag pa

[translation-san] {L,MSA} samāhita

[translation-san] {C} samāpanna

[translation-eng] {Hopkins} meditative equipoise{Gön-chok}; compose the mind for meditation

[translation-eng] {C} collected; concentrated (on); composed; obtained; immersed in; entered into

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary