Parameter (weight)
Beginner
One of the numbers a trained AI model has learned. Big models have billions of them, and all have to be stored somewhere.
Novice
A learned number in a neural network, mostly the weights of its matrix multiplications. Memory needed = number of parameters × bytes per parameter: 2 bytes each in 16-bit formats, 1 byte in 8-bit.
Expert
Weight footprint is bytes. Inference also needs activations and a KV cache; training adds gradients and optimizer state, typically several times the weight footprint.