Complex sentence: A financial endowment is a transfer of money or property donated to an institution, usually with the stipulation that it be invested, and the remain intact in perpetuity or for a defined time period.
Split into simpler sentences: A financial endowment is a transfer of money or property donated to an institution. In some circumstances an endowment may be required to be spent in a certain way or alternatively invested, with the to remain intact in perpetuity or for a defined time period.