Word for describing moderate movement speed

Solution 1:

Try this:

• Low speed
• Medium speed
• High Speed

This is simpler than trying to find a midpoint word between "slow(ly)" and "quick(ly)". This is the terminology you would see on a three-speed kitchen mixer, or a three-speed hair dryer.

Actually, on the speed-control labels these are often shortened to: - LO, MED, HI

Solution 2:

If you want something between slow and fast, you can try Average

A number expressing the central or typical value in a set of data, in particular the mode, median, or (most commonly) the mean, which is calculated by dividing the sum of the values in the set by their number: the proportion of over-60s is above the EU average of 19 per cent

or Medium.

The middle quality or state between two extremes; a reasonable balance: the song soon discovers a happy medium between thrash and catchy pop