ravenna

As a noun tours

is .

As a verb tours

is (tour).

As a proper noun ravenna is

province of emilia-romagna, italy.

As a proper noun ravenna

is province of emilia-romagna, italy.

As a letter d is

the fourth letter of the.

As a numeral d is

cardinal number five hundred (500).

As a symbol d is

deuterium, when it needs to be distinguished from ordinary hydrogen.