寅 is the zodiac sign of the Tiger itself, used in compounds or as a standalone sign; 寅年 explicitly means the year.
Standard kanji spelling using the zodiac kanji 寅.
Katakana spelling of とら, sometimes used for emphasis or in informal contexts.
Mixed kana-kanji spelling, common in casual writing.
Irregular kanji usage; 歳 is not standard for zodiac years. Marked as irregular kanji usage.
Compound of 寅 (tora, 'Tiger', the third sign of the Chinese zodiac) and 年 (toshi/doshi, 'year'). The reading とらどし is a straightforward combination.