In English grammar, an abstract noun is a noun or noun phrase that names an idea, event, quality, or conceptâfor example, courage, freedom, progress, love, patience, excellence, and friendship. An abstract noun names something that can't be physically touched. Contrast with concrete noun.
The adult human brain weighs on average about 1.2â1.4 kg (2.6â3.1 lb), or about 2% of total body weight, with a volume of around 1260 cm3 in men and 1130 cm3 in women, although there is substantial individual variation.
Differences in weight and size of a person's brain does not correlate with differences in mental ability. The adult human brain normally weighs from 1.0 to 1.5 kg (2Â¼ to 3Â¼ lbs). The work of the brain is similar to a combination of a computer and a chemical factory.