For the purposes of this chapter:
(a) Improvements are not a parcel separate from the land on which they are situated.
(b) An undivided interest is a parcel separate from the whole assessment.
(c) A lien is the amount created by the assessment of personal property, or leasehold improvements, or possessory interests; or the amount levied against property by a taxing agency or revenue district when such amount is not determined by the application of a tax rate on a valuation of property. A lien includes any special assessment bond, or installment thereof, together with interest and charges authorized and accruing thereto. A lien also includes any charge of any nature whatsoever authorized by law to be levied against property by any taxing agency or revenue district.