In the discourses I am reading there are terms or concepts I don't know or don't know the Buddhist meanings/interpretation. These concepts I guess are explained elsewhere and may be it is assumed that the reader of the Suttas already knows them.https://www.accesstoinsight.org/lib/aut ... wayof.html
..in attending to the phenomena of mind and body summed up in the "four arousings of mindfulness": body, feelings, consciousness, and mental objects.
Earnestness may also be explained, as it has been by some, as the four mental aggregates of feeling, perception, consciousness and formations, proceeding with application of mindfulness and clear comprehension [satisampajaññayogena pavatta cattaro arupino khandha appamado].
This group of materiality is that of the pure octad consisting of the Four Great Primaries [mahabhuta] symbolized by earth, water, fire and air, and the four derived from these: color, smell, taste and nutritive essence [pathavi apo tejo vayo vanna gandha rasa oja].
I am looking for a book(s)/resources that present definitions and explanations of basic/core/important terms and also theories of Buddhism. Please suggest user-friendly, comprehensive resources on Buddhist (meditation-oriented) philosophy for beginners.