A barrier, hardship or stumbling block.
a combination of two or more cells electrically connected to work together to produce electric energy.
The state of being focused on a particular goal, craft or outcome.
A scientific or industrial process, invention, method or advancement.
a permanent road laid with rails, rail, commonly in one or more pairs of continuous lines forming a track or tracks, on which locomotives and cars are run for the transportation of passengers, freight, and mail.
the exclusive right granted to an inventor by a government to manufacture, use, or sell an invention for a certain number of years.
a person who works for another in order to learn a trade.
protected from or not exposed to danger or risk; not likely to be harmed or lost.
An inventor with over 60 patents.
the part of a telephonic or telegraphic device that converts sound waves or mechanical movements into corresponding electric waves or sudden flow of currents.
A system of wires and devices concerned with electricity.
a new, useful process, machine, improvement, etc., that did not exist previously and that is recognized as the product of some unique intuition noticed from ordinary mechanical skill or craftsmanship.
pertaining to the design, use, understanding, etc., of tools and machinery.
the act, state, or right of possessing something.
a mechanical tool or implement, especially one used for delicate or precision work.
a person trained and skilled in the design, construction, and use of engines or machines, or in any of various branches of engineering.
a person who is exceptionally intelligent or creative, either generally or in some specific area.