cost vs expense
Cost and expenditure are closely related. You spend your resources in return for another thing of value.
SUMMARY:
1. Cost is used on something that has returns, while expenses are expenditures used on things that depreciate.
2. Cost is reported in the balance sheet because it means more funds will come to the balance sheet after the expenditure. Expense on the other hand, is reported on the income sheet because it will be taking away funds from the income sheet in making the expenditures.
3. Cost is used when one is buying assets while expense is used on buying liabilities or things that eventually expire.

So, basically Expense is the amount of cost which has expired and Cost is the amount of expense which has not yet expired.

Understanding Expenses

Expenses are incurred, used as a measure for accounting purposes, which measure the financial performance of an organization. Accounting for expense is standardized by Generally Accepted Accounting Principles (GAAP) to provide shareholders, regulators, and management a standard and comparable view of financial information across diverse industries. Technically, an expense is a specific accounting event related to the outflow of cash reducing corporate equity. Expense simply record the event and used to understand ‘what happened’ from an accounting perspective.

Understanding Costs

Costs are derived, used as a measure for economic purposes, which measure the economic performance across multiple dimensions of business, (organization, product, customer, etc.). A cost is a derived value of money consumed to produce a current or future outcome; hence, costs provide management a decision supporting view to improve business economics. Costs are expressed as a value measured in relationship to a causal volume of consumption.
The Difference between Cost Accounting and Financial Accounting are as follows:
Cost