1. The number underneath in a fraction after simplification
2. A dumbass or a group of dumbasses
1. "I got half marks in that maths test because I didn't simplify to the lowest common denominator"
2. "I got into a fight with a group of the lowest common denominator, mate"
In relation to people, they are the simplest group in a population. They have the simplest opinions, the simplest views and the simplest lifestyles. They are the unsophisticated (which is not correlated to the amount of happiness they have - in fact, living a simple life may make you even more happy than living a sophisticated one). Because these people do not think as much as a sophisticated person, they tend to be more naive and more gullible to gut feelings, and the ingrained culture and social laws that are around them. Their trust is easily earned.
In terms of politics, this can be taken advantage of when politicians use their persona and the gut feelings of their audience to gain followers, even when their policies and views might be to their disadvantage.
Those GOP candidates like to target the lowest common denominators in each state because it's easy followers for them. I mean, who would follow Rick Santorum because of a sweater vest?
Phrase meaning base or crass. Used to describe ideas associated with sex or innuendo. Similar to the phrase "his mind is in the gutter."
"It's embarrassing inviting Dave to my parents' house; he always takes the conversation to the lowest common denominator."
The lowest common denominator is the least attractive girl among a group of girls; or a single girl that though not attractive is the ONLY girl so if you can fuck her you will.
At a party
John Doe: There's no girls left...
Ben Doe: There's that girl
John Doe: Hell no! She's the lowest common denominator. I do have some self respect!
Ben Doe: Fine then I'll take her...Anyone have a bag?