apple of one's eye

WordReference Random House Unabridged Dictionary of American English © 2025

ap′ple of one's eye′, 

1. something or someone very precious or dear:
   His new baby girl was the apple of his eye.

• origin, originally in reference to the pupil of one's eye (in Old English simply æppel; compare Old High German apful with similar sense); later misunderstood

WordReference Random House Learner's Dictionary of American English © 2025

ap•ple /ˈæpəl/   n. [countable]

1. Plant Biology the usually round red, green, or yellow fruit of a small tree of the rose family.
2. the tree itself.

Idioms

3. Idioms apple of one's eye, one greatly loved or valued:
   That child is the apple of her father's eye.

WordReference Random House Unabridged Dictionary of American English © 2025

ap•ple  (ap′əl), n. 

1. Plant Biology the usually round, red or yellow, edible fruit of a small tree, Malus sylvestris, of the rose family.
2. Plant Biology the tree, cultivated in most temperate regions.
3. Plant Biology the fruit of any of certain other species of tree of the same genus.
4. Plant Biology any of these trees.
5. Plant Biology any of various other similar fruits, or fruitlike products or plants, as the custard apple, love apple, May apple, or oak apple.
6. anything resembling an apple in size and shape, as a ball, esp. a baseball.
7. Sport [Bowling.] an ineffectively bowled ball.
8. Drugs, Slang Terms [Slang.] a red capsule containing a barbiturate, esp. secobarbital.

• Balto-Slavic *āblu-. Cf. Avalon
• pre-Celtic *ǫblu; Lithuanian óbuolas, -ỹs, Latvian âbuol(i)s (with reshaped suffix), Old Prussian woble, perh. Thracian (din)upla, (sin)upyla wild pumpkin, Old Church Slavonic (j)ablùko (representing *ablù-ko, neuter)
• * apljaⁿ); Old Irish ubull (neuter), Welsh afal, Breton aval
• Gmc *aplu (akin to Old Norse epli
• bef. 900; Middle English appel, Old English æppel; cognate with Old Frisian, Dutch appel, Old Saxon apl, appul, Old High German apful (German Apfel), Crimean Gothic apel

Collins Concise English Dictionary © HarperCollins Publishers::

apple / ˈæp^əl/ noun

1. a rosaceous tree, Malus sieversii, native to Central Asia but widely cultivated in temperate regions in many varieties, having pink or white fragrant flowers and firm rounded edible fruits
   See also crab apple
2. the fruit of this tree, having red, yellow, or green skin and crisp whitish flesh
3. the wood of this tree
4. any of several unrelated trees that have fruits similar to the apple, such as the custard apple, sugar apple, and May apple
   See also love apple, oak apple, thorn apple
5. apple of one's eye ⇒ a person or thing that is very precious or much loved

Etymology: Old English æppel; related to Old Saxon appel, Old Norse apall, Old High German apful