تَعَاوَنُوا

signifies بَعْضُهُمْ بَعْضًا ↓ أَعَانَ, (S, Msb, K,) They aided, helped, or assisted, one another; (MA;) as also ↓ عَاوَنُوا; (Msb;) and ↓ اِعْتَوَنُوا, (S, K,) in which the و is preserved because it is preserved in تعاونوا with which it is synonym; (Sb, S;) and also ↓ اِعْتَانُوا, according to IB, who cites as an example a verse in which نَعْتَانُ occurs; but this correctly means نَأْخُذُ العِينَةَ [belonging to article عين]. (TA.) One says, تَعاونوا عَلَي الأَمْرِ They aided, helped, or assisted, one another [lit. against, meaning, to accomplish, the affair]. (MA.)