Point estimation is the application of an estimator to the data in order to learn about a certain population parameter.
Point estimation is the application of an estimator (a statistic) to the data in order to learn about a certain population parameter. This parameter may be a fixed number as seen by classical or frequentist statistics or it may be a random variable itself as in Bayesian statistics. Common methods of point estimation are ordinary least squares, maximum likelihood, the method of moments or Bayes' estimators.
For further information see:
Lehman, E.L. and Casella, G. (1998) "Theory of Point Estimation", 2nd edition, Springer Verlag Inc., New York