Taxable income is the amount on which tax will be calculated on.
Taxable income = total income (gross income - exempt income) - allowable deductions + taxable capital gains.
Gross income is the amount of worldwide income that you earned during the tax year, excluding income that is of capital nature.
In tax terms, income is the total gross income you earned during the tax year less exempt income. Exempt income is income which is not taxed e.g. local dividends, donations received.
Taxable capital gains is the taxable portion of money derived from selling your possession, e.g. sale of your house.