Precise measurements are ones in which there is very little spread about the mean value. 

Precision depends only on the extent of random errors – it gives no indication of how close results are to the true value. 

Be careful not to confuse accuracy, precision and resolution. Accuracy is how close to the true value a reading is; precision is a measure of reproducibility – how close together your results are – how much random variation they have; resolution is the smallest change detectable with your equipment.