| ancient Rome |
a civilization cultivated by the city-state of Rome from the 8th century B.C.E. through its development as a republic and its collapse as an empire in the 5th century A.D. |
| armature |
a coil-wrapped iron core that rotates in a magnetic field to induce electrical current in a generator, or that produces motion in an electrical motor when current is passed through it. [1/4 definitions] |
| bead |
a small, generally round object, usu. made of glass, wood, or the like with a hole through its center for stringing to make necklaces or for decorating clothing. [1/8 definitions] |
| cross out |
to remove (something) by drawing a line through it. |
| filament |
in an electrical device such as a light bulb, a fine wire that lights or heats up when current is passed through it. [1/3 definitions] |
| filter |
a piece of paper or other porous material, such as charcoal, used to remove solids or other impurities from fluids or gases that pass through it. [1/7 definitions] |
| guideway |
a channel or groove that defines the path for something moving through it. [1/2 definitions] |
| gulch |
a stony ravine with steep sides, esp. one having a seasonal stream running through it. |
| lens |
a piece of molded or ground transparent material such as glass, whose surfaces are curved so as to cause the divergence or convergence of light rays passing through it. [1/3 definitions] |
| magnifying glass |
a lens that enlarges the image of objects seen through it. |
| permeable |
of a substance, being such that gas or liquid can penetrate or diffuse through it. |
| pinchcock |
a clamp fitted onto a flexible tube to regulate or prevent the flow of liquid through it. |
| Polaroid |
trademark for a substance able to polarize light passing through it, used to reduce glare. [1/2 definitions] |
| quartz lamp |
a mercury-vapor lamp, enclosed within transparent quartz, that emits ultraviolet rays when an electric current is passed through it. |
| solenoid |
a coil of wire, usu. in spiral form, that produces a magnetic field when electricity flows through it. [1/2 definitions] |
| storage cell |
a cell that may be recharged by passing an electric current through it in the direction opposite to the flow of current it discharges. |
| turbidimeter |
an instrument that measures the turbidity of a fluid by the degree of scattering of a light beam passed through it. |
| water gap |
a crosswise break in a mountain ridge, cut by the stream that flows through it. |
| well2 |
a vertical space within a building that extends through its floors and contains the stairs, an elevator, or heat and air shafts. [1/7 definitions] |