"Yes this is true,
but they are not three letter "programming words"." The term "word" exists in computing, and it is not relevant to DNA." - bobdsmith
The term "word" exists in computing to denote a grouping of Binary bits that comprise an instruction. The analogy in DNA are the three bases (mathematical Base-4 instead of Binary Base-2) that are grouped together on each successive rung of the DNA double-helix ladder.
The computing "word" expresses a command instruction to the CPU. The DNA double-helix rung likewise expresses an amino acid, start command, or stop command (read: "Instruction") in the genome processing.