erector

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One that erects.
• noun A muscle that makes a body part erect.

from The Century Dictionary.

• noun One who or that which raises or erects.
• noun One who builds, establishes, or founds.
• noun A workman employed to put in place the steel part of buildings, bridges, or ships.
• noun A machine, such as a derrick, used to place material in position in any structure.

from the GNU version of the Collaborative International Dictionary of English.

• noun One who, or that which, erects.
• noun (Anat.) A muscle which raises any part.
• noun (Physics) An attachment to a microscope, telescope, or other optical instrument, for making the image erect instead of inverted.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A person who, or a device which erects.
• noun anatomy Any of several muscles that make parts of the body erect.
• noun An attachment to a microscope, telescope, etc. for making the image erect instead of inverted.
• noun astronautics A vehicle used to support a rocket for transportation and for placing the rocket in an upright position within a gantry scaffold.