Hetusahetukaduka

Abhidhammapiṭaka · Paṭṭhāna (3) · Vol. 42 · Section 121

[121] A phenomenon (dhamma) that is both a root (hetu) and accompanied by roots (sahetuka) is a condition for a phenomenon that is both a root and accompanied by roots by faculty condition (indriya-paccaya): it is to be specified as "faculty"; all nine (sections) in full.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 1 other place

Vol. 42 · Section 106 — Hetusahetukaduka