Between

The animal was not big or small; it was between the two.

The car was not fast or slow; it was between the two.

The music was not too loud or too soft; it was between the two.

The level of difficulty was not easy or hard; it was between the two.

The restaurant was between expensive and cheap.

The movie was not scary or funny; it was between the two.

The relationship between the two countries is currently strained.

The hikers walked between the trees in the forest.