ecchymosis
Concise Oxford English Dictionary © 2008 Oxford University Press:
ecchymosis /ˌɛkɪˈməʊsɪs/
▶noun (pl. ecchymoses /-siːz/) Medicine a discoloration of the skin resulting from bleeding underneath, typically caused by bruising.
– origin C16: mod. L., from Gk ekkhumōsis ‘escape of blood’.
'ecchymosis' also found in these Oxford entries:

