Individual Medley (IM)

This is when you swim equal parts of each of the four competition strokes, in a specific order. That order is:

1. Butterfly
2. Backstroke
3. Breaststroke
4. Freestyle

So a 100m IM would be:

1. 25m Butterfly
2. 25m Backstroke
3. 25m Breaststroke
4. 25m Freestyle

See also: FrIM