נכנס — to enter

נכנס nikhnás, “enter, go in,” is a nif'al verb from the root כ־נ־ס. The citation form makes the binyan's נ־ easy to see, but that nun belongs only to the past and present: the future and infinitive replace it with a doubled first root consonant, and the infinitive and true imperative begin הי־. Learn the principal parts together: נִכְנַס – נִכְנָס – יִיכָּנֵס – לְהִיכָּנֵס.

Complete paradigm

Everyday second-person plural past normally retracts its stress, as shown above. Dedicated feminine-plural future and imperative forms exist in careful paradigms, but modern Hebrew uses תיכנסו / ייכנסו / היכנסו for groups of every gender.

Where the nun went

In the past and present, נ־ is visible: נכנסתי, נכנס, נכנסת. In the future, the historical nun assimilates into the first root letter, so כ takes a dagesh: יִיכָּנֵס. Ktiv male writes the prefix vowel with a second yod, hence ייכנס, not יכנס. The infinitive and true imperative use the same doubled-root stem after הי־: להיכנס, היכנס.

This is a binyan-wide mechanism rather than an irregularity of one word. The nif'al overview explains the alternation, and nif'al infinitives and imperatives shows why conversational commands so often use תיכנס instead of formal היכנס.

The destination takes ל־

נכנס is intransitive. When a destination is named, Hebrew marks it with ל־: לחדר, לבנק, לאתר. It never turns that destination into a direct object with את. This differs from English enter, which can take a bare object: English says “enter the room,” but Hebrew conceptualizes the room as a goal, “go in to the room.”

The place can nevertheless be omitted when the situation already supplies it, and directional words can replace a named place. The precise rule is therefore: a named nominal destination takes ל־, not that every occurrence must pronounce a destination.

One spelling, several cells

Unpointed נכנס is both past 3ms נִכְנַס and present ms נִכְנָס. Israeli Hebrew pronounces both nikhnás, so context—not spelling or sound—supplies the tense. נכנסת is more crowded still:

A preceding pronoun often resolves the person; a time expression resolves the tense. Without one, the reader waits for the rest of the clause.

Extended destinations

The same goal structure extends beyond physical motion. A law נכנס לתוקף, “comes into force”; information נכנס לראש, “gets into one's head”; a person נכנסת להיריון, “becomes pregnant”; and someone may להיכנס לחובות, “get into debt.” These are not random prepositions: each complement is still construed as the state entered.

כניסה on signs and tickets

The action noun כניסה is often learned before the verb because it appears on doors, tickets and notices. כניסה חופשית means free admission; אין כניסה means no entry; דמי כניסה are an admission fee; כניסה למנויים is an entrance for subscribers or members. In כניסת שבת, the construct form כניסת names the onset of Shabbat, conventionally at sundown.

Key Takeaways

• Learn נכנס – נכנס – ייכנס – להיכנס as one set; the visible נ־ of past and present becomes doubling in the future and infinitive.
• A named destination takes ל־, never את; the destination can be unspoken when context supplies it.
• נכנס is past or present, and נכנסת has three common readings.
• The goal frame extends naturally into נכנס לתוקף, נכנס לראש, נכנסה להיריון and נכנס לחובות.
• כניסה is the everyday noun on entrances, tickets and notices.