An aliyah (or aliyah, Hebrew ; pl. עליות, aliyot; "ascent" or "going up") is the calling of a member of a Jewish congregation up to the bimah for a segment of the formal Torah reading. A person receiving an aliyah is called an oleh (male) or olah (female).
The person who receives the aliyah goes up to the bimah before the reading and recites a blessing for reading of the Torah. After the portion of the Torah is read, the recipient recites another blessing.
Babylonian Jewry completed the reading of the Torah within one year. Palestinian Jewry adopted a triennial cycle (Megillah 29b). The reading of a selection from the Prophets originated in the time of the Mishnah (Megillah 24a). This practice probably began after the canonization of the Bible and the ensuing effort by Jews to highlight the Prophets.
Process
The Torah reading consists of a series of aliyot: three on normal weekdays, seven on Shabbat, and other numbers on holidays.
Before each aliyah, a synagogue official (called a gabbai) calls up one person to receive that aliyah. Only men are eligible in Orthodox and some Conservative congregations, elsewhere both men and women are eligible.
Men are called with: Ya'amod (Let him arise), [Hebrew Name] ben (son of) [Father's Hebrew name] [Ha-Kohen (the Kohen) / Ha-Levi (the Levite)], (the name of the Aliyah in Hebrew). In synagogues where women may receive aliyot, women are called with: Ta'amod (Let her arise), [Hebrew Name] bat (daughter of) [Father's Hebrew name] [Ha-Kohen (the Kohen) / Ha-Levi (the Levite)], (the name of the Aliyah in Hebrew).
The recipient recites a blessing over the Torah reading, then the Torah is read, then the recipient recites a second blessing. In many congregations, the recipient then stands to the side of the bimah during the next person's reading.
In most congregations, the oleh does not themself read the Torah aloud. Rather, they recite the blessings before and after the reading, and during the reading itself they stand near the Torah while a practiced expert, called a ba'al k'ri'ah ("one in charge of reading"; sometimes ba'al ko're), reads the Torah with cantillation for the congregation. In some congregations the oleh follows along with the expert, reading in a whisper.
In Yemenite communities, the oleh reads the portion themself, while another person, usually a young boy, recites the Targum after each verse.
After the last aliyah, half-kaddish is recited. When the Torah is read in the afternoon, kaddish is not recited at this point, but rather after the Torah has been returned to the Ark.
Kohen and Levi aliyot
According to Orthodox Judaism, the first oleh (person called to read) is a kohen and the second a Levite (assuming such people are present); the remaining olim are yisr'aelim — Jews who are neither kohen nor levi. The first two aliyot are referred to as "Kohen" and "Levi," while the rest are known by their number (in Hebrew).
This order was ordained to avoid public competition for the honor of being first.
If a kohen is present but a Levite is not, the same kohen who was called up for the first aliyah receives the second aliyah as well. If a kohen is not present, any Jew can be called up for any aliyah, but it is the custom in some congregations to then give the first Aliyah to a Levite.
Orthodox Judaism recognizes limited exceptions from the general principle that a Kohen is called first. For example, there are cases where calling a kohen first would prevent individuals celebrating special occasions from each having an aliyah. These include a groom celebrating an ufruf aliyah before a wedding, or a thirteen-year-old boy from celebrating his bar mitzvah aliyah. In large synagogues, multiple celebrations at the same time can result in a shortage of aliyot. In these situations, the Kohen is requested to forgo his birthright in respect to the needs of accommodating the occasion. Although halachically, the kohen is entitled to refuse giving up his first aliyah, the kohen will usually agree out of respect for the occasion.
In Conservative Judaism
The Conservative Rabbinical Assembly's Committee on Jewish Law and Standards has ruled that the practice of calling a kohen to the first aliyah represents a custom rather than a law, and thus, a Conservative rabbi is not obligated to follow it. However, some Conservative synagogues continue to follow it.