Cash means “money” and does not include credit or kind.
Fund includes every thing like credit or kind.
For example, a supplier supplies material on credit for which payment is not made immediately. Till the payment is made by us, the supplier has given us money’s worth of goods. Similarly services would also be provided. Thus fund could mean, either “physical cash” or “credit” for supply of goods or services. Hence, at times, the term “fund” also refers to money or money’s worth (OR) cash or kind.
Another example is in case capital is brought into an enterprise in a form, other than cash; say in the form of land or building or machinery or vehicle. This is also fund but would not fall under the category of cash.