I don't know if the engineering field has the same conventions, but in biology we use "fold" as it was used in the paper.
When comparing the signal of two things, the fold change is how many times one is bigger than the other (basically A/B). If A is 15-fold higher than B then it's 15x B.
What you described is the Log2 Fold Change (log2(A/B)), meaning that if A has a log2FC of 15 over B, its signal is 2^15 times higher, hence ≈32,000x.
What you described is the Log2 Fold Change (log2(A/B)), meaning that if A has a log2FC of 15 over B, its signal is 2^15 times higher, hence ≈32,000x.