What's the difference between bigamy and trigamy?

Bigamy

Definition:

(n.) The offense of marrying one person when already legally married to another.

Example Sentences:

(1) On a day that a local newspaper claimed that a police warrant had been issued for his arrest on a charge of bigamy , Mandla was not to be seen.
(2) He has faced criticism during the Republican race for comments made in a 2003 interview that appeared to equate consensual homosexual acts with incest, bigamy or adultery – comments that outraged equality activists , even after Santorum said they had been misinterpreted .
(3) While the marriage act excludes the union of people on the grounds of age and bigamy, it does not rule out same-sex couples, said human rights lawyer Kate Eastman , acting for the ACT.
(4) In America there was one in the 1940s – Ida Lupino – who made rather good, often provocative low-budget movies about bigamy, social snobbery, ambition, the state of women, and she, interestingly, was born in this country and was lured to Hollywood as a young woman, where she was an established actor before she started directing.
(5) The 34-year-old from Cardiff was sentenced to 16 years in prison for charges including rape, bigamy, voyeurism and the new offence of forced marriage.
(6) The man admitted four counts of rape, forced marriage, bigamy and voyeurism.
(7) He has been sentenced to four years in prison for that crime, plus 16 years for rape, a year for bigamy and a year for voyeurism, all to run concurrently.
(8) There are reports that police want to charge him with bigamy and that he may be forced to reveal in court whether he has sold the TV rights to his grandfather's funeral.
(9) He was held over alleged crimes of bigamy and tax evasion but was released without charge.
(10) Reports then said he was being investigated for tax evasion, bigamy and spreading pornography online.
(11) Mandla has been dogged by allegations of bigamy and trying to sell the TV rights to his grandfather's funeral, which he vehemently denies.