dilatation

US /ˌdɪl.əˈteɪ.ʃən/
UK /ˌdɪl.əˈteɪ.ʃən/
1.

sự giãn nở

the process of becoming wider or more open, or the act of making something do this:

:
Dilatation of blood vessels is always associated with increased blood flow and increased blood pressure.