Searches for B-0 decays to combinations of two charmless isoscalar mesons

We search for B meson decays into two-body combinations of eta,eta('),omega, and phi mesons from 89 x 10(6) B(B) over bar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We find the branching fraction B(B-0 --> etaomega) = (4.0(-1.2)(+1.3)+/-0.4) x 10(-6) with a significance of 4.3sigma. For the other decay modes we set the following 90% confidence level upper limits on the branching fractions, in units of 10(-6): B(B-0 --> etaeta) < 2.8, B(B-0 --> etaeta') < 4.6, B(B-0 --> eta'eta') < 10, B(B-0 --> eta'omega) < 2.8, B(B-0 --> etaphi) < 1.0, B(B-0 --> eta'phi) < 4.5, and B(B-0 --> phiphi) < 1.5.