a tree with a round fruit with firm juicy flesh and a thin (green, red or yellow) skin
emerald in color
Cases of word usage
1) a (usually hard) center (with seeds) of such fruits is the apple and pear (core)
2) a seed (especially) of a lemon, orange, apple or pear; a short note of a time-signal on the telephone or radio (pip)
3) having a sharp taste (like that of vinegar, a lemon or an unripe apple etc); having a taste of having gone bad; bad-tempered (sour)
