IPA: /ˌvɛnəˈsɛkʃən/
KK: /vɛnəˈsɛkʃən/
A medical procedure in which a vein is cut or punctured to draw blood or administer medication.
The doctor performed a venesection to collect a blood sample for testing.
Venesection is formed from "ven" (from Latin "vena", meaning vein) and "sectio" (from Latin, meaning cutting). The word refers to the act of cutting into a vein, typically for bloodletting or medical purposes.
Think of 'vein' ('vena') and 'cutting' ('sectio') to remember that venesection means cutting into a vein.