Upagupta 

An important saint (Arhat) who resided in the region of Mathurā sometime between the 3rd century bce and the 1st century ce. Upagupta is not mentioned in the Pāli Canon, and although featuring in non-canonical Pāli literature does not become prominent in Theravāda countries until around the 12th century as a result of his importance in the Sanskrit sources. In the Sarvāstivāda tradition he is the fifth patriarch after Mahākaśyapa, Ānanda, Madhyāntika, and Śāṇakavāsin, and in the Ch'an tradition he is regarded as the fourth. He features prominently in the avadāna literature (chapters 21 and 27 of the Divya-avadāna contain the fullest account of his life), and he is said to have lived during the time of Aśoka, who held him in high esteem.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)

upa-gupta mfn. hidden, concealed

• m. N. of a king

Sanskrit-English Dictionary, by M. Monier William

nyer sbas

[translation-san] upagupta

[translation-eng] {Hopkins} Upagupta (p.n.)

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary