stales says Having the same Latin root works for me.

Yeahbut©, raven¹ (http://www.bartleby.com/61/88/R0058800.html)
and
raven² (http://www.bartleby.com/61/89/R0058900.html)
are no more the same words than are
cleave¹ (http://www.bartleby.com/61/89/C0398900.html)
and
cleave² (http://www.bartleby.com/61/90/C0399000.html)
or
let¹ (http://www.bartleby.com/61/96/L0129600.html)
and
let² (http://www.bartleby.com/61/97/L0129700.html).