normal twin

normal twin

[′nȯr·məl ′twin]
(crystallography)
A twin crystal whose twin axis is perpendicular to the composition surface.
References in periodicals archive ?
The Sahara's engines were the normal twin cylinder units, each producing 12hp and each with a separate fuel tank.
The oldest and the most persistent theory of visceral inversion is that twins are often mirror image of each other that a single individual with situs inversus represents a survivor whose normal twin has died in utero.
Mrs Garret, aged 26, now faces a wait to see if the normal twin will survive the trauma of surgery.
Conjoined twins result from incomplete separation of monozygotic, monochorionic twins early in embryonic development, resulting in body parts of the otherwise normal twins remaining fused throughout development.
In a group of 22 monozygotic twin pairs discordant for schizophrenia, the affected twins had significantly more total obstetrical complications, more labor-delivery complications, and more neonatal complications than the normal twins or a matched control group.