What is the meaning of Countable_additivity?

5-letter words containing

• 5-letter words containing k

• 5-letter words containing r

• 5-letter words containing u

• 5-letter words containing m

• 5-letter words containing e

5-letter words starting with

• 5-letter words starting with n

• 5-letter words starting with i

• 5-letter words starting with s

• 5-letter words starting with c

• 5-letter words starting with e

5-letter words in the middle

• 5-letter words in the middle o

• 5-letter words in the middle a

• 5-letter words in the middle t

• 5-letter words in the middle t

• 5-letter words in the middle t

5-letter words ending with

• 5-letter words ending with i

• 5-letter words ending with h

• 5-letter words ending with c

• 5-letter words ending with a

• 5-letter words ending with e

5-letter words excluding

• 5-letter words excluding t

• 5-letter words excluding s

• 5-letter words excluding r

• 5-letter words excluding a

• 5-letter words excluding e