The Tipiṭaka in Three Languages

Suññatavāra

Abhidhammapiṭaka · Dhammasaṅgaṇī · Vol. 34 · Section 392

[392] What on that occasion is one-pointedness of mind (cittass'ekaggatā)? Whatever stability (ṭhiti) of the mind (citta) there is on that occasion — this on that occasion is the one-pointedness of mind.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 5 other places