Longman Dictionary of Contemporary English - common

~1 adj 1 »A LOT/LARGE AMOUNT« existing in large numbers or happening often and in many places  (Heart disease is one of the commonest causes of death.) + among  (Bad dreams are fairly common among children.) it is common for sth to happen  (It's very common for new fathers to feel jealous of the baby. | common belief/assumption/practice etc)  (It's a common but false assumption that all mentally ill people are violent.) 2 »SAME/SIMILAR« usually before n, no comparative common aims, beliefs, ideas etc are shared by several people or groups  (They had a satisfying sense of working towards a common goal.)  (a theme that is common to all her novels) common ground (=shared opinions, beliefs etc among people who are usually separate)  (The two parties met to establish some common ground.) 3 »SHARED BY EVERYONE« usually before n, no comparative belonging to or shared by everyone in a society  (These problems are common to all societies.) the common good (=the advantage of everyone)  (Do they seriously think they're acting for the common good? | common knowledge (=something everyone knows))  (In a small town everyone's actions are common knowledge. | common land (=owned by the public) | by common consent (=agreed by everyone))  (Joe was chosen as captain by common consent.) 4 common courtesy/decency a polite way of behaving that you expect from people  (It's only common courtesy to write and thank them for the present.) 5 »ORDINARY« only before noun, no comparative ordinary and not special in any way  (The common people will not benefit from these reforms. | common salt | the common man (=ordinary people) | common-or-garden BrE slang (=very common and ordinary)) 6 »PERSON« especially BrE old-fashioned an offensive word for someone from a low social class  (Stop that! People will think we're common. | as common as muck BrE (=extremely common)) 7 common practice a usual or accepted way of doing things  (Sending kids away to school was common practice among the upper classes.) 8 the common touch the ability of someone in a position of power or authority to talk to and understand ordinary people  (He's made it to the top without losing the common touch.) ~2 n 1 have sth in common (with sb) to have the same interests, attitudes etc as someone else  (To my surprise, I found I had a lot in common with this stranger.) 2 have sth in common (with sth) if objects or ideas have something in common, they share the same features  (Their methods have a lot in common.) 3 in common with sb/sth in the same way as someone or something else  (In common with a lot of other countries, we're in an economic recession.) 4 a large area of grass in a village that people walk or play sport on 5 technical having the same relationship to two or more quantities  (5 is a common factor of 10 and 20)