Incorrect spelling, explanation: auxilliary is not the correct form of the word. The correct spelling is auxiliary. In English, consonants are doubled for specific reasons, such as when adding a suffix to a short-vowel word (e.g., run → running) or to differentiate between similar words (e.g., cancel vs. cancelled in British English). However, none of these rules apply to auxiliary. There’s no grammatical or phonetic reason for a double -l. Auxilliary is simply a common misspelling and is not recognized as an alternative form.

Correct spelling, explanation: the word auxiliary originates from the Latin term auxilium, meaning help or aid. English adopted the word in the late Middle Ages (14th–15th century) as auxiliary, maintaining its Latin-based spelling and meaning. Thus, the word has consistently been spelled with a single -l due to its Latin roots, and English preserved this structure. No, auxilliary does not have a separate etymology because it is not a valid word. It is simply a misspelling of auxiliary.

Definition of auxiliary:
1. Noun, an auxiliary person or thing
The school relies on an auxiliary to assist teachers with managing large classes during exams.
During the hospital’s busiest hours, the auxiliary helped by organizing patient records and distributing supplies.
2. Adjective, providing supplementary or additional help and support
The factory installed an auxiliary pump to ensure operations could continue during maintenance on the main system.
The military base had an auxiliary power supply to handle emergencies during power outages.

Collocations with auxiliary:
Some of the most commonly used collocations include:
1. Auxiliary unit: a smaller or secondary group that supports the main group in an organization, often in emergencies or specific situations.
The auxiliary unit of firefighters was deployed to provide additional support during the forest fire.
2. Auxiliary equipment: refers to supplementary equipment used alongside main equipment to enhance functionality or provide backup.
The laboratory installed auxiliary equipment to increase testing capacity.
3. Auxiliary services: secondary or supportive services that assist the primary operations of an organization or system.
The university offers auxiliary services, such as housing and meal plans, to its students.

Incorrect spelling

Incorrect spelling