As professionals, we prefer logo, logotype, mark, symbol, wordmark, icon, visual identity or signature. With this many choices it is no wonder others have settled on the irreverent bug. Incidentally, a long-time friend in Mumbai told me of some of the general names for logo in India include pintu (pint sized), chintu (tiny), dabboo (fat) and kaka (small one). (But depending on the specific region, language and even community in India, kaka also can mean poo-poo, as elsewhere. I guess context is everything, when calling a logo kaka in India.)
But whether we designed it, manage it, or just live with it, having a name for the logo appears to fulfill some human need. Some companies provide a formal name, such as The Monogram (GE). Here are a few logos and their officially sanctioned names:
