What is Umbrella Fund?

Legal Definition
An umbrella fund is a collective investment scheme that exists as a single legal entity but has several distinct sub-funds which, in effect, are traded as individual investment funds.

This type of arrangement originated in the European investment management industry, most notably with the SICAV (an open-ended collective investment). The SICAV model was copied for the UK Open-ended investment company (OEIC) and offshore fund models.
-- Wikipedia
Legal Definition
Mutual fund investing in other funds. Also known as fund so funds.