This section defines the core concepts and distinctions used throughout the site. These concepts form the shared vocabulary for understanding salary structures, employment relationships, taxation, and social‑security systems.
Each concept is explained in isolation, using neutral and descriptive language. The purpose is to clarify meaning and reduce ambiguity, not to guide decisions or describe individual situations.
Terms such as salary, income, tax, or contribution are often used interchangeably in everyday language, even though they refer to different elements of employment and public‑finance systems.
Misunderstanding these distinctions makes it difficult to interpret payslips, compare systems, or understand how employment is financed. The Concepts section exists to provide stable reference definitions that other pages can rely on without repeating or redefining terms.
The concepts in this section fall into several broad groups.
Concept pages are canonical definitions. Other sections of the site may reference them to clarify meaning but do not redefine them.
The Concepts section is not intended as a navigation hub or reading sequence. Concepts may be consulted independently as needed.
Each concept is described at a structural and institutional level only.
The following pages provide detailed definitions and structured comparisons of key concepts used throughout the site.
Gross Income Definition
Total income before any deductions are applied.
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Net Income Definition
Income remaining after taxes and mandatory deductions.
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Income vs Earnings
Difference between work-related earnings and broader income concepts.
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Income vs Wages
Distinction between employment wages and total income categories.
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Income vs Compensation
Comparison between what individuals receive and total employer cost.
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Income vs Benefits
Difference between earned income and social or statutory support.
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Gross Pay vs Total Labour Cost
Employee-facing pay compared to full employer cost.
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Income Tax Definition
Mandatory tax applied to income under national law.
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Social Security Definition
Public systems providing protection against social risks.
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Social Contributions vs Taxes
Difference between earmarked contributions and general taxation.
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Source‑Based vs Residence‑Based Taxation
Whether income is taxed where it arises or where the person resides.
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Statutory Rate vs Effective Rate
Legal rates compared to actual paid share of income.
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Tax Residency
Determines which country has the right to tax income.
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Residence vs Taxation Scope
How residence affects which income is taxable.
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Residence vs Domicile
Factual residence compared to long-term legal home.
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Residence vs Habitual Residence
Temporary living compared to stable centre of life.
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Residence vs Nationality
Living location compared to legal citizenship status.
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Residence vs Immigration Status
Living in a country versus legal permission to stay/work.
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Residence vs Employment Location
Where someone lives vs where work is performed.
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Residence vs Posting
Permanent living compared to temporary cross-border work.
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Residence vs Social Insurance
Living location compared to social-security coverage.
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Residence vs Social Residency
Factual residence compared to social-security system assignment.
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Statutory vs Contractual
Legal obligations compared to agreement-based conditions.
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Mandatory vs Optional
Legal requirements compared to voluntary arrangements.
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Mandatory Coverage vs Eligibility
Obligation to participate vs entitlement to benefits.
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Work Permit vs Residence Permit
Authorisation to work compared to permission to live in a country.
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