The noun (Substantiv/Nomen) Eintrag is masculine in German. Therefore, the correct definite article in the nominative singular is der. So, you say: der Eintrag.
(entry)
Eine Information, die in ein Register, eine Liste oder ein Buch geschrieben oder eingegeben wird.
A piece of information that is written or entered into a register, list, or book.
Ich habe einen Eintrag in meinem Kalender gemacht.
I made an entry in my calendar.
German grammatical gender can be tricky at first, as it doesn't always seem logical - like with the neuter 'das Mädchen' (the girl). But here's the good news: Even though you won't find a rule for every word and some things just need to be memorized, there are quite a few helpful patterns and rules! These are real guideposts and can make your life significantly easier. So it's definitely worth knowing them!
Nouns ending in -ant are usually masculine. Common in words of Latin/French origin, often describing people or technical/scientific terms
Nouns ending in -ast are usually masculine. Usually found in scientific or technical terms, often from Greek/Latin origins
Nouns ending in -ich are usually masculine. Common Germanic suffix, often in everyday vocabulary and adjective-derived nouns
Nouns ending in -ig are usually masculine. Germanic suffix forming nouns from adjectives or verbs, often describing containers or enclosed spaces
Nouns ending in -ling are usually masculine. Forms nouns describing people or things with certain characteristics, often with diminutive or derogatory meaning
Nouns ending in -or are usually masculine. Latin origin, typically describing machines, devices, or professional roles
Nouns ending in -us are usually masculine. Latin/Greek origin, common in scientific, academic, and cultural terms
Strong Verb Nouns: Derived from strong verbs, describing the action itself or its result are usually masculine. Very reliable rule in German
Examples:
Cars: Car brands and models are generally masculine in German
Examples:
Currency: Most currency names are masculine, except for a few notable exceptions
Days, Months, and Seasons: These temporal nouns are consistently masculine
Male Persons: Nouns referring to male individuals are masculine
Examples:
Mountains and Mountain Ranges: Most mountain names are masculine, except for specific ranges
Non-German Rivers: Rivers outside German-speaking countries are typically masculine
Nouns ending in -gang are usually masculine. Typically describing paths or processes
Examples:
Nouns ending in -mut are usually masculine. Typically describing states or qualities
Examples: