Unis. stands for Unison. It means that you should play together.
Unison.
The verb for unison is "unify."
Unison in French is 'unisson'.
together
At the same time.
Yggdra Unison happened in 2009.
Unison Industries's population is 2,200.
Unison Industries was created in 1980.
The word "unison" is a noun.
The birds flew in unison.
"Unison" can be either a noun (much more often) or an adjective. Example as an adjective: The fourth part of the oratorio is a unison anthem. Examples as a noun: The fourth part of the oratorio is sung in unison; how pleasant it is for a family to dwell in unison!