co-operate
From LSJ
English > Greek (Woodhouse)
v. trans.
P. and V. συμπράσσειν, συνδρᾶν, συνεργεῖν, συλλαμβάνειν, V. συμπονεῖν, συγκάμνειν, συνεκπονεῖν, P. συναγωνίζεσθαι; see aid.
Co-operate with: use verbs given with dat.
The fleet which was to have co-operated with Cnemus: P. ναυτικὸν ὃ ἔδει παραγενέσθαι τῷ Κνήμῳ (Thuc. 2, 83).