well-known

Remarkable is a related term of well-known.

As adjectives the difference between remarkable and well-known

is that remarkable is worthy of being remarked or noticed; noticeable; conspicuous; hence, uncommon; extraordinary while well-known is familiar, famous, renowned or widely known.

Essential is a related term of well-known.

As adjectives the difference between essential and well-known

is that essential is necessary while well-known is familiar, famous, renowned or widely known.

As a noun essential

is a necessary ingredient.

Valuable is a related term of well-known.

As adjectives the difference between valuable and well-known

is that valuable is having a great value while well-known is familiar, famous, renowned or widely known.

As a noun valuable

is a personal possession such as jewellery, of relatively great monetary value; — usually used in plural form.

Well-known is a related term of illustrious.

As adjectives the difference between well-known and illustrious

is that well-known is familiar, famous, renowned or widely known while illustrious is dignified.

As adjectives the difference between primary and well-known

is that primary is the first in a group or series while well-known is familiar, famous, renowned or widely known.

As a noun primary

is a primary election; a preliminary election to select a political candidate of a political party.

As a verb primary

is to take part in a primary election.

Principal is a related term of well-known.

As adjectives the difference between principal and well-known

is that principal is principal, main while well-known is familiar, famous, renowned or widely known.

Critical is a related term of well-known.

As adjectives the difference between critical and well-known

is that critical is inclined to find fault or criticize; fastidious; captious; censorious; exacting while well-known is familiar, famous, renowned or widely known.

As a noun critical

is a critical value, factor, etc.