Is the eukaryotic cell a colony?

I am not a biologist, but have an interest in botanic. I am familiar with the evolutive process undergone by algae, that progressed from unicellular to multicellular organization via colony association. I know only superficially the endosymbiosis theory, but it seems to me a different process that colony. Basically colony seems to be an association, wears endosymbiosis seems to imply fagocitosys. Or may both processes be considered similar? What is your opinion?

I'm only an aspiring biologist, myself.Endosymbiosis doesn't necessarily imply phagocytosis - it could develop from parasitism, for example. As I understand Margulis's original idea it was suggested that the original cilia cells would have lived as external symbionts in a colonial arrangement and then, over time, become more closely joined until they formed the arrangement we see today.I don't think Dawkins meant the term 'colony' to be taken in any technical manner but simple as a group living together.