Easton's Bible Dictionary (1897)/Apple
Apple: (Heb. tappuah, meaning "fragrance").
Apricot or quince
Probably the apricot or quince is intended by the word, as Palestine was too hot for the growth of apples proper. It is enumerated among the most valuable trees of Palestine (Joel 1:12), and frequently referred to in Canticles, and noted for its beauty (Joel 2:3,5; 8:5). There is nothing to show that it was the "tree of the knowledge of good and evil." Dr. Tristram has suggested that the apricot has better claims than any other fruit-tree to be the apple of Scripture. It grows to a height of 30 feet, has a roundish mass of glossy leaves, and bears an orange coloured fruit that gives out a delicious perfume.
Apple of the eye
The "apple of the eye" is the Heb. ishon, meaning manikin, i.e., the pupil of the eye (Proverbs 7:2). (Comp. the promise, Zechariah 2:8; the prayer, Psalm 17:8; and its fulfilment, Deuteronomy 32:10.)
Apple of Sodom
The so-called "apple of Sodom" some have supposed to be the Solanum sanctum (Heb. hedek), rendered "brier" (which see) in Micah 7:4, a thorny plant bearing fruit like the potato-apple. This shrub abounds in the Jordan valley. (See ENGEDI.)