Siamese twins (linguistics) conjoined twins from Siam. In the context of the English language, this word was first used and popularised by H. W. Fowler, a renowned lexicographer. The most common conjunctions used in a phrase that constitutes Siamese twins are "and" or "or." The structure of any Siamese twins phrase has words that are related in some way. The words constituting a Siamese twins phrase may be synonyms, antonyms, include alliterations or similar-sounding words that often rhyme. Other varieties of Siamese twins may also be possible. Examples below are split into various tables; some may belong in more than one table but
Monoamniotic twins Monoamniotic twins Monoamniotic twins are identical twins that share the same amniotic sac within their mother’s uterus. Monoamniotic twins are always identical, always monochorionic and are usually termed Monoamniotic-Monochorionic ("MoMo" or "Mono Mono") twins. They also share the placenta, but have two separate umbilical cords. Monoamniotic twins develop when an embryo does not split until after formation of the amniotic sac, at about 9-13 days after fertilization. Monoamniotic triplets or other monoamniotic multiples are possible, but extremely rare. Other obscure possibilities include multiples sets where monoamniotic twins are part of a larger gestation such as triplets, quadruplets, or more. Monoamniotic