What is the meaning of Equivalence_relation?

5-letter words containing

• 5-letter words containing p

• 5-letter words containing t

• 5-letter words containing h

• 5-letter words containing s

• 5-letter words containing t

5-letter words starting with

• 5-letter words starting with t

• 5-letter words starting with o

• 5-letter words starting with t

• 5-letter words starting with n

• 5-letter words starting with f

5-letter words in the middle

• 5-letter words in the middle n

• 5-letter words in the middle p

• 5-letter words in the middle e

• 5-letter words in the middle e

• 5-letter words in the middle e

5-letter words ending with

• 5-letter words ending with i

• 5-letter words ending with t

• 5-letter words ending with i

• 5-letter words ending with c

• 5-letter words ending with z

5-letter words excluding

• 5-letter words excluding s

• 5-letter words excluding n

• 5-letter words excluding i

• 5-letter words excluding u

• 5-letter words excluding l