What is indirect costs?

which can,t be traced per unit

the cost that cannot be associated with a cost object in an economic and feasable way

the cost which is not directly related in the making of final product.

Indirect costs are costs that are not directly accountable to a cost object (such as a particular project, facility, function or product).
Indirect costs may be either fixed or variable.
Indirect costs include administration, personnel and security costs.
These are those costs which are not directly related to production.
Some indirect costs may be overhead.
But some overhead costs can be directly attributed to a project and are direct costs.

Direct costs are directly attributable to the object.
In construction, the costs of materials, labor, equipment, etc, and all directly involved efforts or expenses for the cost object are direct costs.
In manufacturing or other non-construction industries the portion of operating costs that is directly assignable to a specific product or process is a direct cost.
Direct costs are those for activities or services that benefit specific projects, for example salaries for project staff and materials required for a particular project.
Because these activities are easily traced to projects, their costs are usually charged to projects on an item-by-item basis.

Spend more than one product and are difficult to link or distributed directly to the final product units or are costs incurred in performing a particular activity any spent on productive activity as a whole or marketing activity in general.

Indirect costs are those costs that are not classified as direct.
Examples of indirect costs are : Salaries of administrative and clerical staff providing normal support activities in the department, college or school Office supplies including postage Local telephone calls Memberships - See more at: http://www.uaa.alaska.edu/research/OSP/direct-vs-indirect-costs.cfm#sthash.6vRRoyIE.dpuf

the cost which cannot be identified directly or economicaly for a product

Costs not specifically  identifiable or traceable  with some product or cost centre are Indirect costs.This can be allocated to various products or cost centres based on some common factors only.

Indirect costs are costs that are not directly accountable to a cost object (such as a particular project, facility, function or product).
Indirect costs may be either fixed or variable.
Indirect costs include administration, personnel and security costs.
These are those costs which are not directly related to production.
Some indirect costs may be overhead.
But some overhead costs can be directly attributed to a project and are direct costs.

Indirect cost are cost that not directly related to the production.
In construction accounting, indirect cost are office personnel salaries and wages, office utilities billing, insurance, client and consultant fees, office supplies, office staff transportation billing, transportation fees of equipment, customs fees, engineering fees.