Other forms: leeches
A leech is a worm that fastens on and drinks blood. A leech attached itself, leeches in the pond, pull the leech off.
Medicine still uses them: after reattaching a finger or an ear, leeches drain blood the veins cannot yet carry away, which saves tissue. Their saliva contains a powerful anticoagulant. A leech in the old sense was also a doctor, and the two words are related.
1nounleechA worm that fastens on and drinks blood.
“After wading through the swamp, he found a leech stuck to his leg.”
leech is a worm.
Old English laece means both the worm and a physician. The two senses ran together because doctors used the worm.
Old English
lǣċe — blood-sucking worm
Middle English
leche — blood-sucking worm
English, today
leech
From Middle English leche (“blood-sucking worm”), from Old English lǣċe (“blood-sucking worm”), akin to Middle Dutch lake "blood-sucking worm"; > modern Dutch laak.
Etymology from Wiktionary, CC BY-SA