: a lateral (see lateralentry 1 sense 2) outgrowth from a plant stem that is typically a flattened expanded variably shaped greenish organ, constitutes a unit of the foliage, and functions primarily in food manufacture by photosynthesis
(2)
: a modified leaf (such as a bract or sepal) primarily engaged in functions other than food manufacture
Noun
I heard the rustle of the autumn leaves.
a pile of dead leaves
The trees drop their leaves in the fall, and new leaves grow again in the spring.
The trees have not yet come into leaf. Verb
we must have spent hours leafing through wallpaper books before we found something we both liked
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Noun
Some of the most common diseases affecting sweet corn are Northern corn leaf blight, common rust, and common smut.—Sj McShane, Martha Stewart, 3 Apr. 2026 There are majorana leaf and Japanese plum leaf extracts to soothe, protect, and promote an optimal scalp environment, along with argan oil, the brand’s signature ingredient rich in nourishing vitamin E, antioxidants, and essential fatty acids.—Cathy Nelson, InStyle, 3 Apr. 2026
Verb
At the site, trees are leafing as workers add finishing touches.—Aria Jones, Dallas Morning News, 25 Mar. 2026 But other begonia varieties have foliage that can hold its own in the garden when the plants aren't flowering, too, like the Polka Dot begonia (Begonia maculata) and the orange-leafed 'Autumn Crinkle' begonia, a rhizomatous hybrid.—Derek Carwood, Better Homes & Gardens, 12 Mar. 2026 See All Example Sentences for leaf
Word History
Etymology
Noun
Middle English leef, from Old English lēaf; akin to Old High German loub leaf
First Known Use
Noun
before the 12th century, in the meaning defined at sense 1a(1)