Dic: investment (some of its countable and uncountable usages)

N-UNCOUNT:

1. usu with supp, oft N in n△Investment is the activity of investing money.

• He said the government must introduce tax incentives to encourage investment...
• to encourage foreign investment (OALD)
• investment income (OALD)
• [investment in something] This country needs investment in education. (OALD)

4. usu N of n △Investment of time or effort is the spending of time or effort on something in order to make it a success.

• I worry about this big investment of time and effort.
• The project has demanded considerable investment of time and effort. (N-VAR acc.to. OALD)

N-VAR:

2. usu with supp △An investment is an amount of money that you invest, or the thing that you invest it in.

• You'll be able to earn an average rate of return of 8% on your investments.
• a minimum investment of $10000 (N-COUNT acc.to. OALD)
• a high return on my investments  (N-COUNT acc.to. OALD)
• Our investments are not doing well. (N-COUNT acc.to. OALD)
• We bought the house as an investment (= to make money).  (N-COUNT acc.to. OALD)

N-COUNT:

3. usu sing, usu adj N △If you describe something you buy as an investment, you mean that it will be useful, especially because it will help you to do a task more cheaply or efficiently.

• When selecting boots, fine, quality leather will be a wise investment...
• A microwave is a good investment. (OALD)

..... COBUILD, OALD