Yes, indeed, most relevant in this case probably "time" and "bandwidth", put together, even if you saturate the line for a month, they won't throttle you, so for all intents and purposes, the "data cap" is unlimited (or more precise; there is no data cap).
Of course there are practical limits as you can't make your 100Mb/s connection into a gigabit one (ignoring that you can buy burstable in a datacenter, etc, etc).
Where unlimited falls down is when it refers to a endlessly consumable resource, like storage.