Definition: A thing which can have only (one or the other of) two values.

Alright class, settle down now, let’s dive in with a bow! Today we're tackling "binary," a word that sounds quite neat, It’s a concept crucial, oh so sweet! The dictionary’s right, you see, it’s simple and clear: "A thing which can have only one or the other, my dear!" Think of it like a light switch, on or off, you see? Just two possibilities for you and me. That's binary at its core, a fundamental key, One is "on," and zero’s “off,” for all to agree! Computers understand this code so bright, Using just these two values, day and night. It’s like building with blocks, you see the plan? Just two colors – black or white - a simple scan! So remember, binary's just a "yes" or “no,” A basic foundation, helping knowledge grow! Do you have any questions for me, my dears? Let’s discuss and learn with cheers!