What is the meaning of Formal_system?

5-letter words containing

• 5-letter words containing l

• 5-letter words containing c

• 5-letter words containing m

• 5-letter words containing e

• 5-letter words containing a

5-letter words starting with

• 5-letter words starting with e

• 5-letter words starting with s

• 5-letter words starting with o

• 5-letter words starting with l

• 5-letter words starting with g

5-letter words in the middle

• 5-letter words in the middle s

• 5-letter words in the middle i

• 5-letter words in the middle o

• 5-letter words in the middle e

• 5-letter words in the middle p

5-letter words ending with

• 5-letter words ending with i

• 5-letter words ending with g

• 5-letter words ending with s

• 5-letter words ending with s

• 5-letter words ending with k

5-letter words excluding

• 5-letter words excluding r

• 5-letter words excluding d

• 5-letter words excluding l

• 5-letter words excluding s

• 5-letter words excluding u