The word mezuzah literally means “a doorpost”. The etymology of this word is not entirely clear. Traditional sources connect this word with the root “zuz” – to move. Linguists trace this word to the Akkadian “nazazu” – to stand, or “manzazu” – a doorpost.

In the Scriptures, the word mezuzoth usually means doorposts. However, in a few places it is translated as doors (Proverbs VIII, 34), windows (Kings VII, 5; Septuagint), Temple Gates (I Samuel I, 9) or jambs (Ezekiel XLI, 21). In contemporary colloquial use, mezuzah usually means the commandment or the parchment itself containing the prescribed text of Shema and Vehayah. The Jews of India sometimes name girls “Mezuzah.”

According to tradition, the Jewish people have observed the commandment of mezuzah since it was given at Sinai in the Jewish year 2448 (1312 b.c.e.) It is debatable whether mezuzoth were actually in use during the forty-year journey through the desert, since the temporary huts used for dwelling were most likely exempt from the commandment just as a sukkah-booth is exempt from the mezuzah today. It is safe to assume that the mezuzah became a permanent feature of the Jewish home from the time that the Jews settled in the land of Canaan in the period 2488-2502 (1272- 1258 b.c.e).

One of the earliest known reports of mezuzah observance is found in the Josephus’ Antiquities of the Jews. He writes:

They are also to inscribe the principal blessings they have received from G‑d upon their doors... that G‑d’s readiness to bless them may appear everywhere conspicuous about them.

Josephus notes that mezuzah was, already in his time, an ancient practice among the Jews.

The Dead Sea discoveries have provided many samples of ancient mezuzoth dating back to the Second Temple era.

During the Roman occupation of Judea, Jews were prohibited from observing the commandments of mezuzah, tefillin and others. At the same time, in the Diaspora, the Jews held steadfast to these sacred practices.

There were periods of temporary lapses in the observance of mitzvah mezuzah, particularly in Spain. Rabbi Moses of Coucy visited Spain in 1235 to “reprove the people” as a result of which

thousands and tens of thousands took upon themselves to observe the mitzvoth of tefillin, mezuzoth, and tzitzith.

Details of the observance vary slightly among different Jewish communities. Thus Rabbi Herbert Dobrinsky reports the following variations among Sefardic communities:

Syrian Jews inspect the mezuzah once every year (the law requires inspection twice in seven years).

Moroccan Jews are particular about enclosing the mezuzah in a metal or wooden case on which the letters Shin, Daleth and Yud (spelling the name of G‑d Shad-dai) are written. They also affix mezuzoth on their synagogues (though the law does not require it).

Spanish Jews place the mezuzah vertically. Some tilt it only slightly inward. They are encouraged to buy beautiful cases for their mezuzoth. Spanish synagogues feature mezuzoth. The mezuzoth are inspected only once in seven years.

Rabbi Dobrinsky further reports:

It was a custom of many in Turkey to recite special prayers for health, livelihood, and success, as they were about to leave their houses to face the challenges of the outside world.

Spanish and Portuguese Jews recite a different blessing when affixing a mezuzah for other than oneself. Instead of the traditional Likbo’a mezuzah (which they also say when affixing a mezuzah for oneself) they say Al keviath mezuzah.

The Samaritans,1 who did not accept the oral tradition, do not require a mezuzah to be affixed at the doorpost. Sometimes they affix a stone with the Ten Commandments or Ten Sayings (by which the world was created) to the lintel of the main entrance to their house or place it near the entrances.

The Karaites,2 who also rejected the oral tradition, do not require that a mezuzah be affixed at the doorpost. They affix a blank plate symbolically resembling the Torah Tablets to the entrances of their public buildings and sometimes on private houses.