Definitions

mainline

[meyn-lahyn, -lahyn] / ˈmeɪnˌlaɪn, -ˈlaɪn /

ADJECTIVE

principal

Synonyms

STRONGEST

dominant key leading main major outstanding paramount predominant preeminent primary prime prominent

STRONG

arch capital cardinal champion chief essential first head maximum premier sovereign star superior

WEAK

controlling crowning foremost greatest highest incomparable matchless peerless prevailing second to none stellar strongest supereminent supreme transcendent unapproachable unequaled unparalleled unrivaled

Antonyms

STRONGEST

inconspicuous inessential inferior insignificant last lesser minor nonessential ordinary secondary subordinate trivial unimportant unknown

STRONG

auxiliary least lower poor

WEAK

extra

VERB

inject

Synonyms

STRONGEST

vaccinate

STRONG

inoculate jab shoot

WEAK

give a shot

Antonyms

WEAK

take out

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Mainline and regional trains are still running, but are not always the most reliable alternative.

From Barron's • Feb. 2, 2026

Mainline Protestant denominations, such as the Episcopal Church, often welcome LGBTQ+ Christians looking for a place to worship and of acceptance.

From Salon • Nov. 16, 2025

Mainline, which carries on to Clearbrook, Minn., and Superior, Wis., and delivers crude to markets in Minnesota, northern Illinois, Indiana, Ohio, Michigan and southern Ontario.

From The Wall Street Journal • Nov. 14, 2025

The first pipeline in the Mainline network, Line 1, from Edmonton, Alberta, and was built in 1950.

From The Wall Street Journal • Nov. 14, 2025

The derailment has also hit TransPennine Express services, which use the West Coast Mainline.

From BBC • Nov. 4, 2025

mainline

Example Sentences

Related Words