Tangible Net Worth is another word for Book Value or Net Asset Value. Only the tangible assets and cash are included, and any liabilities are subtracted.
Any depreciation that would otherwise be included for accounting purposes is added back in. Tangible net worth, or book value, is the remaining balance after intangible assets and all liabilities are deducted from net assets.
This is the amount that will be divided among shareholders in the event of a company liquidation, and the minimum that the company would be purchased for by an acquiring company. Shareholders can use this as a bare-minimum estimation of the value of their shares.
Since tangible net worth disregards intangible assets such as intellectual property and goodwill, it reduces the chance that a valuation will be inflated, as is sometimes the case with goodwill especially since it does not have a market value.