Gotrabhū: lit. 'who has entered the lineage of the Noble Ones', i.e. the Matured One.
I. 'change-of-lineage-Moment' gotrabhū-citta is the last of the 4 impulse moments javana cf. viññāna-kicca immediately preceding the entering into an absorption jhāna or into one of the supra-mundane paths see: ariya-puggala A.. Cf. visuddhi VII.
II. The 'Matured One'.;He who is endowed with those things, immediately upon which follows the entrance into the noble path ariya-magga, this person is called a 'Matured One'.; Pug 10. In the Com. to this passage it is said:;He who through perceiving Nibbāna, leaves behind the whole multitude of worldlings puthujjana, the family of worldlings, the circle of worldlings, the designation of a worldling and enters into the multitude of the Noble Ones, the family of the Noble Ones, the circle of the Noble Ones, and obtains the designation of a Noble One, such a being is called a Matured One.; By this state of consciousness is meant the lightning-like transitional stage between the state of a worldling and that of a sotāpanna see: ariya-puggala- Gotrabhū is mentioned in this sense, i.e. as 9th ariya-puggala, in A. IX, 10; X, 16.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.