You could say that. Single malt whisky is any bottling of whisky only from a single distillery; the whisky is made only from malted barley, water, and yeast in pot stills. It may be aged in any barrels the distillery chooses, and usually the best barrels are reserved for these bottlings. Unless the whisky is specifically designated "single barrel" or similar, it is most likely a vatting (mixture) of many different barrels. This is done because the distillery wants to market a consistent product. There may be differently aged whiskies in any given vatting, but if there is an age on the bottle, all of the whisky in the bottle must be at least that old. A pot still is what you usually see pictures of, with a rounded pot and a long neck. One batch at a time is made in it. A bottle of single malt whisky sold by the company that owns the distillery--an "official Bottling", or OB--always has the name of the distillery on the label.
Grain whisky may contain other grains than barley, and it is usually made in a column still. This looks like a tall cylinder, and it can be operated continuously for as long as desired.
The whole idea of a blend is that much of its volume is grain whisky, which is much cheaper to produce, with the malts being added to provide character. Blends vary greatly in quality, depending on the volume of grain whisky and the age and quality of the malts used. Johnnie Walker, for example, sells the very inexpensive Red Label, and the very expensive Blue Label, and several blends in between. Generally, though, blends are less expensive than single malts. Of course the price ranges overlap a lot.
A very broad rule of thumb is that single malts have the name of a place on the label--the distillery name, which is usually the same as the locality it is in--and blends have the name of the company that produces them, often the name of the person who founded the company, or an emblem like Cutty Sark or Famous Grouse. That's a rough rule, though, because some blends use names designed to make them look like single malts, like Glen Andrew.
(kk, no sweat...it's not like I'm the most knowledgeable person here, by any means! I just happen to be here a lot.)