Sentence:  The gradient was about one half of a millidegree at 4.2 * * f but increased to several millidegrees for bath temperatures slightly greater than the | <WSD>l</WSD> point . 
Meaning of the word marked with <WSD> tags:  a metric unit of capacity, formerly defined as the volume of one kilogram of pure water under standard conditions; now equal to 1,000 cubic centimeters (or approximately 1.75 pints)