Why is the initial phase in TCP congestion control called slow start?

Question

Why is the initial phase in TCP congestion control called slow start when actually it is exponential while the additive increase phase has linear congestion window growth?

Answer 1

Slow start was introduced in 1988*. It was called "slow start" because it was slower than the prior approach which was simply blasting packets out without considering the congestion.

Congestion Avoidance and Control by Van Jacobson and Michael J. Karels