Suppose we heat a solid piece of metal. The atoms vibrate increasingly as the temperature is raised and this shows as an overall expansion of the metal. At a certain temperature the amplitude of the vibrations is such that the bonds between the atoms are broken and the atoms are free to move from their previously fixed positions. This is known as the melting point and the metal remains at steady temperature, despite the fact that heat is still being applied, until all the solid atoms become molten. This take up of energy is known as "latent heat of fusion" and it is defined as the energy required to change a solid metal to liquid at the fixed temperature known as the melting point.
http://www.ul.ie/~walshem/fyp/crystal structure.htm

latent heat - specific latent heat, molar latent heat - Delta ...
The specific latent heat (symbol l) is the heat absorbed or released per unit mass of a substance in the course of its isothermal change of phase. ...
science.jrank.org/pages/16430/latent-heat.html - Cached

The use of stepwise differential scanning calorimetry for thermal ...
by WL Kerr - 1994 - Cited by 12 - Related articles
The latent heat of ice melting was linearly correlated with sample weight ... series of small temperature jumps, each followed by an isothermal period. ... The given melting point of the indium standard was 429.78 K. The heat of fusion ...
linkinghub.elsevier.com/retrieve/pii/0040603194800979

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Note added at 57 mins (2010-11-12 09:39:47 GMT)
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trovo anche isothermal hold/holding

(o, più in generale, si potrebbe anche dire isothermal state or condition)

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Note added at 7 hrs (2010-11-12 16:27:24 GMT)
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sosta here means a time span (during which no heat changes are recorded), "phase" in the context would be understood as, say, solid vs liquid phase - that's why i didn't put it in