What is the meaning of Proper_subset?

5-letter words containing

• 5-letter words containing s

• 5-letter words containing r

• 5-letter words containing a

• 5-letter words containing e

• 5-letter words containing c

5-letter words starting with

• 5-letter words starting with e

• 5-letter words starting with g

• 5-letter words starting with e

• 5-letter words starting with k

• 5-letter words starting with m

5-letter words in the middle

• 5-letter words in the middle n

• 5-letter words in the middle e

• 5-letter words in the middle a

• 5-letter words in the middle i

• 5-letter words in the middle e

5-letter words ending with

• 5-letter words ending with l

• 5-letter words ending with n

• 5-letter words ending with l

• 5-letter words ending with k

• 5-letter words ending with i

5-letter words excluding

• 5-letter words excluding o

• 5-letter words excluding e

• 5-letter words excluding e

• 5-letter words excluding a

• 5-letter words excluding t