What does iambic pentameter mean

Its defined by pairing its ten syllables per line into five pairs, and in kind of a stressed and unstressed pattern. Sounding like 1[da Dum] 2[da Dum] 3[da Dum] 4[da Dum] 5[da Dum] (the numbers represent pairs, the brackets are for organization) i did a terrible explanation, but thats kinda the gist, its mainly used in poetry, and pentameter also refers to meters which are patterns of syllables in a line, and since in pentameter, theres five

metrical line

It describes the rhythm that the words establish in a line, which is measured in small groups of syllables called "feet". "Iambic" refers to the type of foot that is used, known as the iamb, which is in English is an unstressed syllable followed by a stressed syllable. "Pentameter" indicates that a a line has five of these "feet".