What is the meaning of Nominal_variable?

5-letter words containing

• 5-letter words containing s

• 5-letter words containing c

• 5-letter words containing t

• 5-letter words containing p

• 5-letter words containing v

5-letter words starting with

• 5-letter words starting with w

• 5-letter words starting with e

• 5-letter words starting with s

• 5-letter words starting with r

• 5-letter words starting with t

5-letter words in the middle

• 5-letter words in the middle h

• 5-letter words in the middle m

• 5-letter words in the middle e

• 5-letter words in the middle e

• 5-letter words in the middle a

5-letter words ending with

• 5-letter words ending with e

• 5-letter words ending with r

• 5-letter words ending with s

• 5-letter words ending with k

• 5-letter words ending with r

5-letter words excluding

• 5-letter words excluding e

• 5-letter words excluding l

• 5-letter words excluding a

• 5-letter words excluding a

• 5-letter words excluding a