These are both from Dictionary.com, though the initial definition provided for HEAT had no scientific entries. Scrolling down got me the scientific British definition provided.
For the purposes of this forum and this thread, we're comparing def #1 against def #1.
Temperature is an arbitrary scale used to quantify an instantaneous thermodynamic characteristic of matter and is expressed as a numeric value from any of several arbitrary scales: Fahrenheit, Celsius (aka Centigrade), Rankine (aka Rankin) and Kelvin (both aka Absolute)
The Fahrenheit scale was developed by physicist Daniel Farhrenheit. On it, zero is assigned to the lowest temperature that could be created at that time (1764), which was accomplished with a brine solution of water, ice and ammonium chloride. An upper value of 90 degrees was originally assigned to what Fahreheit believed to be the average temperature of a healthy human body. This was later changed to 96 degrees and finally, after the freezing and boiling points of water at 1 atm pressure were assigned to 32 and 212 degrees respectively, settled at 98.6 as used today. On all these scales, the assignment of two different values determines the 'size' of a unit degree.
Celsius, also know as Centigrade, was developed by Swedish astronomer Anders Celsius in 1742. It was originally called Centigrade, but in 1942 was officially renamed Celsius to honor the astronomer. It is one of the two scales used in the SI (Metric) system. On this scale, 0 is assigned to the freezing point of water and 100 is assigned to the boiling point of water. The Celsius degree is 9/5ths or 1.8 times the size of the Fahrenheit degree. The well known conversions between Fahrenheit and Celsius are F = C * (9 / 5) + 32 or C = (F - 32) * (5 / 9).
Finally, there are two absolute scales widely used in thermodynamics: the Kelvin scale and the Rankin scale. Both assign zero to Absolute Zero. Kelvin uses a degree sized identically to a Celsius degree while Rankin uses the Fahrenheit degree. The conversion from Celsius to Kelvin is C = K + 273.15. The conversion from Rankin to Fahrenheit is F = R - 459.67 . To convert between Rankin and Kelvin, one only requires the proportionality: R = K * (9 / 5) and K = R * (5 /9).
I have to run some errands so I will discuss heat in a second post when I return this evening. Feel free to kvetch amongst yourelves.