This is the 12245th most frequent Russian word.
инъекцию
Injection.
The word 'инъекцию' here refers to the medical procedure of injecting a substance into the body.
Врач сделал пациенту инъекцию.
The doctor gave the patient an injection.
Here, 'инъекции' refers to the method by which the medication is administered.
Этот препарат вводится путем инъекции.
This medication is administered through an injection.
In this case, 'инъекций' refers to the plural form, discussing multiple injection types or instances.