thrombus
Concise Oxford English Dictionary © 2008 Oxford University Press:
thrombus /ˈθrɒmbəs/
▶noun (pl. thrombi /-bʌɪ/) a blood clot formed in situ within the vascular system of the body and impeding blood flow.
– origin C19: mod. L., from Gk thrombos ‘blood clot’.
'thrombus' also found in these Oxford entries:

