(אִטְבִּח ) is not a real word, but a factitious cabalistic term denoting by its very letters the mode of changing one word into another by a peculiar eommutation of letters. The system on which it is founded is this: as all the letters have a numerical value, they are divided into three classes, in the first of which every pair makes the number ten; in the second, a hundred; and in the third, a thousand. Thus:
דו, גז, בח, אט, every pair making ten.
מס, לע, כפ, יצ, "a hundred.
תם, שן, ר, קוֹ, "a thousand.
Three letters only cannot enter into any of these numerical combinations, ה, נ and ךְ . The first two are nevertheless coupled together; and the last is suffered to stand without commutation. The commutation then takes place between the two letters of every pair; and the term Atbach thus expresses that א is taken for ט, and ב f or ח, and conversely. To illustrate its application, the obscure word מנון, in Proverbs 29:21, may be turned by Atbach into סהדה , testimony (Buxtorf, De Abbreviaturis, s.v.).