Definition
a flat thin green part of a tree or plant that grows on a branch or stem
Origin and usage
Leaf comes from the Old English word ‘lēaf’, which is of Germanic origin and related to the Dutch ‘loof’ and German ‘Laub’.
Examples
At this time of the year in the northern hemisphere, the leaves of deciduous trees change colour and after passing through various shades of red, orange, yellow and brown fall to the ground, there to decompose and return to the soil. This process is triggered by the reduction in daylight hours, which causes the leaves to stop making food using chlorophyll, the biomolecule that absorbs energy from the sun and gives them their usual green colour. The trees have no further use for the leaves and shed them to conserve water and protect themselves during harsh winter conditions.
In many places, such as New England in the US, the spectacle of the foliage changing colour is so beautiful that people make special trips to see it, but even the smallest back garden or city park can offer a dazzling if transient display.
Leaf is one of a number of words ending in ‘f’ that form the plural with -ves, the form ‘leafs’ being reserved for the third person of the verb. A few words ending in ‘f’ like hoof, roof and dwarf have two plurals, both -fs and -ves being acceptable.
Quotations
“Every leaf speaks bliss to me Fluttering from the autumn tree.”
(Emily Brontë)
“I love the chill October days, when the brown leaves lie thick and sodden underneath your feet.”
(Jerome K Jerome)
View the full definition in the Macmillan Dictionary.