Four-letter

You can't say four-letter words on TV.

You had better not use those four-letter words.

Censorship feeds the dirty mind more than the four-letter word itself.

Encoded in a four-letter alphabet in the two intertwined strands of the DNA molecule are the instructions for making all the proteins, each with its specific function, necessary to sustain life.

The algorithm a cell follows when making a protein is extremely complex. Roughly speaking, the coded information – four-letter words – stored in the DNA is copied, translated into a language whose alphabet has twenty letters, edited, and transmitted to the area where the protein is assembled.

You shouldn't use those four-letter words.

You'd better not use those four-letter words.

a four-letter reply, a four-letter insult, a four-letter tirade