del / dell [dɛl]
del – n. – Math an operator upon a function of 3 variables (x,y,z) interpreted as co-ordinates in the right-handed rectangular system for obtaining the partial derivations of a function, for multiplying these derivatives by the unit vectors (I,J,K) along the axes and for adding the results; symbol ( = I/x + J/y + K/z – Leigh Page)
dell – n. – a small, usually wooded hollow or valley