incidental
US /ˌɪn.sɪˈden.t̬əl/
UK /ˌɪn.sɪˈden.t̬əl/

1.
insidental, kebetulan, tambahan
happening as a minor accompaniment to something else
:
•
The discovery was incidental to their main research.
Penemuan itu kebetulan terjadi pada penelitian utama mereka.
•
Any costs incurred will be purely incidental.
Biaya yang timbul akan murni insidental.