(of quantities) imprecise but fairly close to correct
"lasted approximately an hour"
"in just about a minute"
"he's about 30 years old"
"I've had about all I can stand"
"we meet about once a month"
"some forty people came"
"weighs around a hundred pounds"
"roughly $3,000"
"holds 3 gallons, more or less"
"20 or so people were at the party"
Approximately, very nearly.