Maftir
Maftir is the last person called up to the Torah on Shabbat and holiday mornings: this person also reads the haftarah portion from a related section of the Nevi'im.
Informally, the portion of the Torah read or blessed by the maftir is called the "maftir portion", or the "maftir" for short: in a Chumash, the word "maftir" is printed in the margin at the beginning of that portion.
On a normal Shabbat morning, seven people are formally called up to the Torah, and a part of the week's Torah portion is read by or to each of them. The maftir is not counted among the seven, and is sometimes not formally called up by name: on the conclusion of the seventh reading and after reciting Chatzi kaddish, in some communities the gabbai simply calls "maftir" and repeats the last few verses in the presence of the maftir.
On Jewish holidays and certain special Shabbatot, there are readings from two or more Torah scrolls. On these occasions, some call the maftir by name, followed by the word "maftir", and the reading from the last scroll is read in his presence. On Tisha b'Av morning and fast day afternoons, the maftir portion is the third section of the portion.
After the Torah reading, the maftir says the blessings for the haftarah, and in most communities reads it.
Holiday selections
The maftir portion for the Festivals and for Rosh Chodesh that occurs on Shabbat comes from the appropriate paragraph in Numbers 28 or 29, describing the sacrifice for the day.The maftir portion for Shabbat during Chanukah comes from Numbers 7, describing the dedication offering of the Mishkan corresponding to the day of Chanukah where Shabbat occurs.