Bojjhanga
Bojjhanga: 'the 7 factors of enlightenment', are: awareness or mindfulness sati-sambojjhanga, sati, investigation of the law dhamma-vicaya-sambojjhanga energy viriya-sambojjhanga, viriya padhāna rapture pīti-sambojjhanga tranquillity passaddhi-sambojjhanga, concentration samādhi-sambojjhanga, equanimity upekkhā. Because they lead to enlightenment, therefore they are called factors of enlightenment see: XLVI, 5.
Though in the 2nd factor, dhamma-vicaya the word Dhamma is taken by most translators to stand for the Buddhist doctrine, it probably refers to the bodily and mental phenomena nāma-rūpa-dhammā as presented to the investigating mind by awareness or mindfulness, the 1st factor. With that interpretation, the term may be rendered by 'investigation of phenomena'.
See: Seven factors of enlightenment
References
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.