RATED voltage is the voltage on the nameplate - the "design point" for maximum power throughput and safe thermal operation.
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
The resistance-change factor per degree Celsius of temperature change is called the temperature coefficient of resistance. This factor is represented by the Greek lower-case letter “alpha” (α). A positive coefficient for a material means that its resistance increases with an increase in temperature.
the distance between two baselines of lines of type. The word 'leading' originates from the strips of lead hand-typesetters used to use to space out lines of text evenly. The word leading has stuck, but essentially it's a typographer's term for line spacing.
An encoder is classified into four types: mechanical, optical, magnetic, and electromagnetic induction types.
Pulses per revolution (or PPR) is a parameter associated with encoders. Basically, it is a measure of the number of pulses per full revolution or turn of the encoder, with a full revolution being 360 degrees. In essence, it is a measure of an encoder's resolution.